I've spent many years working on cars and trucks and tractors of various sizes and ages so I know my way around machinery. This was a wonderful find. I'm having issues with wife's 4x4. I watched many transfer case videos. They claim to show you how it works, wrong, they just show you the basic internal parts with no explanation, totally worthless in my opinion. This video was excellent at making how it works understandable. Thank you for producing it. I also subscribed because I saw other videos you produced that look very interesting.
This video is one of the best out there along with those of the channel "engineering explained". As an wngineering student it really helped me understand what was actually going on inside those systems. I COULD NOT FIND any good videos to accurately and correctly explain the exaxt thing, how a tranfer case with a torsen works. This video is my savior.
@@WeberAuto i also have a few queations to ask about these and othe video you ve made about understanding differentials. Im trying to built my car and im trying to make the wright choises amd also explore all the possibilities.
Computer models and animations are great and all that but having an actual physical representation of what you're describing right there in front of you is, in my opinion, the best way to teach.
Your explanation always fulfills more than an eight course meal. I appriciate your work and efforts that you put in to make complex things as easy as ABC. You started with a simple TX Case and then took it to center diffs. Reminding the viewers about the 4WD expirience of locking wheels if engaged on paved surface. Thank you very much for such a nice explanation.
I just want to take a minute of time to say thank you for your excellent educational videos, I was in the first class of GM's ASEP program in '84 and its been a while since I wrenched on a car, the last 8 years I've been working on big trucks and MRAP(Mine Resistant Ambush Protected) tactical vehicles in Iraq, Afghanistan and Qatar and now am applying for an automotive technicians job in Iraq that requires ASE certs, your videos have been invaluable to me it's amazing how much I've forgotten hahaha thank you again for YOUR time
Very well explained. Even someone like me with no mechanical knowledge whatsoever is now able to understand the differences between part-time 4WD and AWD.
Great teardown! I've always been curious what the lockable Torsen center diff in my V8 4runner looks like and how it works. One small correction though. Torsen (or or more generally torque biasing differentials) are *not* speed sensitive. They don't care how fast one side is spinning versus the other. They are "torque sensing" (thus the brand Tor-sen), or more generally "torque biasing" which means they are simply a torque multiplier. An open diff always sends the same torque to both sides of the diff (seriously). A torque biasing diff (TBD) uses the angled teeth on the worm style gears to multiply the torque of the low traction (low load) side and send more torque to the higher traction (higher load) side. If an open diff always has a torque bias ratio (TBR) of 1:1, a TBD might have a TBR of say 2:1 so if the low traction side will hold X lb-ft of torque before it slips, the TBD will send 2X lb-ft to the high traction side. Of course the flaw is that we have zero traction on one side then zero times 2 is still zero, and you get zero torque to both sides of the diff (no matter how fast one side is spinning relative to the other). And that is in fact the case. You can still get stuck with only one tire off the ground at one end of the vehicle (ask any Humvee owner). That is why this type of center diff still needs a locking mechanism for extreme low or zero traction situations. And Torsen is not a predecessor (or substitute) for brake driven stability or brake driven "diff locking" (really brake driven torque transfer).. My V8 4Runner has a center Torsen diff + brake driven yaw stability control + A-TRAC (their name for brake driven diff locking). When the center diff manual lock is engaged, they disable stability control, but keep A-TRAC. It all works very well together even for pretty extreme rock crawling. Newer vehicles don't use Torsen center diffs simply because it's cheaper. The brakes have to do more work to achieve a similar result, but it's used so rarely it wins in the cost/benefit calculation.
I have a quastion for you , the uploader of the video, or anyone that might know. I have a audi q5 with a tosrsen. Torsen obviously doesnt lock. Audi has an edl system to simulate lock using the torsen. However, since the 4runner, landcruiser, l200, use this type of locker(torsen with a tranfer case), could i add that compoment to my audi. Im not talking about the planatary gears for the low range, but just the locking function.
@@WeberAuto You, sir, are amazing! Have just one question concerning the last part (40:00 onwards): 1) In a vehicle with a center diff, one usually has 2H (2WD), 4H and 4 Low. Therefore it's never really an AWD unless you have an extra Auto mode. Therefore, here, in your demonstration, a 2H, 4H, 4L vehicle with a center diff, won't the vehicle either be a 2WD or a 4WD (be it in 4H or 4L) but never an AWD? If yes, then why have a center diff anyway if it functions exactly like a regular tcase here? I think, the center diff allows the front and rear axles to rotate at different speeds in 4H. For example, that is how it is in the Ford Ranger/Endeavour and the LDV D90. Or am I missing something here? Please note that we will not talk about locking diffs at all. :)
@@RealAutoReviews There are many center differential transfer cases with AWD on GM and RAM trucks and SUVs. They function differently than a traditional transfer case because they have a computer-controlled clutch pack that limits the difference in speed between the front and rear driveshafts.
@@WeberAuto awesome! One last question for the day: An AWD vehicle cannot have JUST a clutch pack, right? I mean, there has to be a differential or a traditional transfercase with it. A standalone clutch pack would do nothing, right?
@@RealAutoReviews There are AWD transfer cases with just a computer-controlled clutch pack, no center diff, but still has a drive gear, chain, and driven gear to deliver power to the front output shaft. The New Process 136 is a 1-speed example. The NP 236 and 246 are two-speed examples
Sir, thank you very much! I have been wondering all about this for a while, and you are the only one who could explain. Not only that, but you explained very well. Thank you!
Took some time to find your video with a more detailed explanation of these mechanisms. There are lots that explain the basics that I already knew. Mainly I wanted to know exactly what changes inside my NP242 (2001 Grand Cherokee 4.0) that gives it part time 4WD and fulltime 4WD. I had envisioned a setup with side gears and pinion gears that somehow locks for part time operation. Also watched your other video explaining cross over AWD. WOW...I'll stick with the relatively basic Jeep that doesn't even have locking hubs to fail even if it is a bit of a gas guzzler. Great job explaining. Thank you!! PS: I really like the idea of using worm gears to create a limited slip in the Torsen differential. Brilliant.
Being a planetary centre diff, does this create a torque bias between front and rear axles? Love your videos.....nothing like it out there. Can NOT believe you only have 69k subscribers......I would have expected to see another 0 on the end of that! Thanks for the content....great to see this depth of knowledge and practical demonstration shared for free.
Yes, a variable torque bias depending upon the rear-to-front driveshaft speed differential. Typically as much as 70-80% to the rear dependent upon the gear ratio of the planetary gear set.
Which car or truck models have the center differential transfer case shown in the second part of this video? As I understand, this transfer case supports both 2x4 and all-wheel drive on dry pavement. But for some reason, most truck and SUV manufacturers use either partial 4WD (shown in the first part of this video) or full-time AWD (that does not allow disconnecting the front wheels and drive in 2x4 RWD mode). For example, 2024 Toyota Tacoma lineup has 2x4, 4WD without center differential and one AWD trims (the AWD being Limited one), but no 4WD with a center differential. What is the reason for that - cost optimization, complexity, market segmentation?
Some say he's a finely tuned machined, and can communicate with intelligent life on many planets. All we know is he's Jack Nicholsons articulated teaching Stig! (You are a bloody fine teacher John)
You videos are so informative it's god sent. I think it helps me understanding what is causing the loud bang when my 3rd gen 4runner disengage from 4WD.
This is fantastic. At 28:40, you mention the 4Runner transmission is an older style. I have that transmission in my 04 V8 AWD 4Runner, and the vehicle has both vehicle stability control and traction control. It doesn't pulse the brakes front and back, but does pulse the brakes for VSC . Putting it in 4WD turns off VSC, though as the vehicle has open front and rear differentials, the traction control will still pulse the brakes to help each axle find traction. Thought you'd like to know a bit more about the vehicle that transmission is out of.
@@WeberAuto I should also mention when VSC kicks in it kills the engine power, so you don't end up with an unbraked wheel taking all the engine torque.
this is the content that I've been looking for all this time ... how is it different from the way ordinary 4WD works and how all wheel drive works. thank you for the information
Hi John , although this isn't trade related for me ; and I had different certification , and refresher courses in a life time , this was precise , and enjoyable !.. Great watching !
Toyota Landcruiser and Lexus LX570/GX460 use both a Torsen center differential AND electronic traction control to moderate wheel spin. Belt and suspenders. Center diff is also lockable and two range in all three models.
Great video. As Nima someh mentioned in a previous comment, I'd also love to see a video on the Subaru STI center differential. The DCCD used on the WRX STI is very advanced, so a video demonstrating its lock up characteristics, asymmetrical torque split, and mechanical/electromagnetic limited slip capabilities would be awesome. Thanks!
14:40 ... actually, as long as your front lockers are locked in, that "chain gear" will be pushed by the front wheels--- so actually, it will be practically syncronized already by the front and rear wheels spinning at the same speed (given that your tires are the same size and you DO have the front wheels locked in)--- I suppose that if you 'don't have your manual wheel lockers locked in, then the syncro would have to spin that entire front drivetrain in order to shift into 4x4 (as you said)--- but in that scenario, your 4x4 wouldn't work anyway without stopping and locking in the front wheels....... I guess as little as you need to shift into 4x4 on the fly, that syncro wear from having to spin that entire front drive train just to shift smoothly, would not be too excessive. (just thinking out loud,... Great presentation as always. I have a 2002 7.3 diesel F350-- with the manual transfer case, manual locking hubs-- and 6spd manual ZF650 transmission (i believe thats what its called)--- I haven't fully checked yet, but I hope you have a video on that transfer case, i want to see what is inside of it-- whether it has a chain or direct gear drive........... I actually pulled my 6spd manual trans out of this truck and pulled it all apart and put in new syncornizers.. lol.. lets just say, it was a learning experience and I had to build my own 2 foot puller with some 3/4 inch all thread and some steel I welded up--- I could have bought this puller but it was $500, so I just made my own... I also had to make my own press, that I rigged up with a 32 ton bottle jack. I'm definitely fascinated by transmissions. Love the channel.
Spot on! I was going to write the same thing, but found your comment first. Nice to see someone who understands what he's talking about. Does it bug you when everyone says a locked differential "sends equal torque to both wheels" or "equal power to both wheels"? Because you probably understand that an open differential sends equal torque to both wheels and a locked differential sends equal motion to both wheels. I've also always wondered why people say 2WD mode is more efficient than 4WD when they don't have wheel lockers and all the shafts are always spinning, regardless. I'm talking about AWD cars like the Honda CR-V with its hydraulic pump system to engage rear drive when a speed differential is detected, or the Toyota Sienna with clutch packs sending power back. I mean, the rear axle and driveshaft are always spinning anyway. Is it really that they've just avoided having to add a center differential by keeping the rear disengaged most of the time? The full time 4WD system in my GX470 with Torsen center differential should be equally efficient, just cost more due to mechanical complexity, right?
Wait, isn't that forward gear set already spinning with the moving front wheels? Having it in 2WD just prevents power being added to the front diff, but that doesn't actually mean it's stopped when not engaged while the vehicle is moving.
Around 15:00 you say that the output shaft for the fwd is statonery and so the sync has tot do a really good job. But is that the case? I think the output fwd is rotating in direct relation to the forward wheels ( but there is no torque coming from the engine ) and so the speed difference might not be that high. That would only happen if while driving in 2wd the rear wheels start to spin and the driver would want to engage 4wd (on the fly). But then again the speed difference would not be that high ( slip generally occurs in lower gears ) and the torque needed to sync fwd and rwd is not that high since the rear wheels are sliping in the first place. Correct? That is not to say the sync mechanism does not need to be sturdy.
This demonstration makes it sound like the High/Low planetary gear has something to do with the 2WD/4WD function, but it is 2 separate systems. You can drive in 2WD low no problem mechanically because it is 2 separate functions.
Those worm-like planetary gear things in the Torsen C Type Differential, look like the things that compress air in a supercharger, a special type of impeller which tries to increase the psi of the air, but a spooler, a type of impeller in a turbocharger, causes air to get spooled in big radiuses of psi compressed out of the exhaust.
I will stay with my regular 4WD transfer case. The AWD is confusing, but you rely on the ABS to stop the "open differential wheel spin" which then allows power to the non spinning axle, be it front or rear. The other problem with the AWD is tire circumference with the Torzen (spelling) center diff assembly. If one tire was older or somehow smaller in circumference it would cause problems in the drivetrain. Check out iATN in their older case studies. GM mini vans had this problem. Destroyed transfer cases and/or differentials would happen. By having the ABS slow the spinning tire, the non slipping axle would take over and the center diff xfer case would handle it.
16:10 Wouldn't there only be a couple 100 rpm difference at most though? Since the 4wd gear is already spinning at roughly the same speed since its connected to the front diff which is being turned by the road/wheels
Your explanation of the operation of the gears and clutches and sliders in the transfer case is very interesting. There is however a mistake you are making when talking about the synchros in the transfer case. The chain and front output shaft is always turning when the vehicle is in motion so that you can do shift on the fly. They parts are being driven by the front axle turning the front propeller shaft so they do not have to be spun up to speed to match. If you had a set of Warn hubs on the vehicle and they were unlocked then the shaft would not be turning and that would prevent you from having shift on the fly anyway.
Thanks for your feedback! It depends upon the vehicle and what mode of the transfer case is selected. If it is only an AWD vehicle, then I agree with you, but if it is multimode with a 2WD option, the front axle can disconnect on some models. Hubs are old school, there are actuators that can disengage and engage the front axle as you drive.
How is the front axle going to disconnect if the only connection to the front axle is through the drive shaft and the differential and the solid hubs? My Jeep Liberty is not AWD but has a 242 transfer case (centre differential) with no locking hubs so it runs all the time as do all the other standard current 4x4's that I have seen. If you do have "actuators" (locking hubs) then I would agree with you.
Newer design axles use actuators (not automatic hubs) to disconnect or connect the right or left axle shaft from the differential side gears as you drive. The actuator is located just outside of the differential housing. Disconnecting the axle shaft(s) allows the front ring and pinion gear to stop rotating. This allows for less frictional drag on the vehicle and improved fuel economy. Old school vehicles like the Jeep Wrangler, Liberty, Dodge trucks, Durango, etc do not disconnect the front axle shafts unless they have hubs. This forces the front ring and pinion to constantly rotate and drive the front driveshaft at the same time. Even the new solid axle RAM trucks use an actuator to disconnect the right axle shaft from the differential so the front driveshaft will stop rotating while driving in 2WD. I hope that helps.
Do you have any videos that cover the clutch disc engagement for 4WD used on the BorgWarner 44 and 48 series transfer cases used on Ram 1500s and the MP 3020 transfer cases used on many Jeep products. Do they have wear problems? Do they effectively act as a differential? Do their electronics require specific tire sizes (seems to be programmed for BW 44-44). Do they provide driver control of transfer case locking (at least for the BW transfer cases the answer seems to be no).
Hi proffessor , could you plese explain also the Opertion mechanisms of center differential with viscous coupling and locking CD which is used in Mitsubishi Super select transmission , to me CD powers 2 output shaft front and rear axle , operaton
So... the 2013 Tundra has no option to select N on the transfer case yet in theory, it’s TC is mechanically capable of such... why no ability to select this position? Would be nice to be able to flat tow. Maybe not with a Tundra but the 4runner or Tacoma would be nice to be able to pull behind an RV.
Theoretically in the open (full slip) case, tire grip all around, awd mode, that planetary type diff will split torque front to rear unequally based on the lenght of arm (radius) that the input uses (acts upon). Say it enters via the carrier, it'll give more torque to the outside ring vs to the sungear. It looked like it entered through the outside ring here. Can you please clarify where it enters and what end gets more torque in this case?
If I remember correctly, the input is on the ring gear. The rear output is connected to the sun gear, the front output is connected to the planet carrier.
Thank you so much for your videos. You go into great detail on everything and you explain every move and operation. I am actually having troubles with a nv5600 right now and am going to have to rebuild it but there is not one video or decent book out there to read and rebuild it. If you have any suggestions for me please do so. Thank you again.
spartan1071 Hi, the NV5600 is a very heavy, huge, cast iron, heavy-duty, transmission. You must have a strong transmission jack to even remove it. It also requires several special tools to disassemble and reassemble properly. We no longer have that transmission here at our school, so I can't help you with a video. The only trucks that used it (to my knowledge) were Dodge trucks. The Chrysler Training Tenters had a very good book for the theory of operation and overhaul procedures back when that transmission came out in the late 1990's. You might check on eBay to see if you can find one there. Best wishes.
WeberAuto yes I know I own that truck you speak of. It's a dodge ram 3500 Cummins. The transmission weighs in at 450lbs. Without the transfer case connected. I do heavy a very large transmission jack rated for two tons. I almost every till known to man. But thank you for the info I will definitely try to find the book you speak of. If you think of anything else please let me know.
For the t-case, typically all newer trucks run synthetic gear oil front & rear, many still run dino in front… I believe the auto shift engages the diff first to prevent smokin the synchro in case. The weight of gear oil is what it is regardless of syn or dino based & 75/90 ain’t much different than 80/90.
One doubt teacher, in this kind of differential front wheel to rear wheel differential ratio is not equal to one. I mean when the power input shaft is locked. If above ratio is not one, dose it mean there is a power distribution happen with the same ratio?
On most truck manuals, it is mentioned not to exceed certain speed when driving in 4-low. Why is that? what can go wrong if driving in 4-low at higher speeds (let us say 30-40 MPH) (Please note I am referring to driving in soft sand, as in desert safari)?
That is well noted and thank you for your reply and the extremely informative video. But putting the engine aside, any extra wear or tear to transfer case or other transmission parts at higher speeds in 4low?
Due to the added gear reduction, you just run out of gears in low range. The additional gear reduction in low range makes it easier to break things as well if you aren't careful.
Any particular reason I can't use the low range of the transfer case in 2WD and/or as a gear splitter? That would make a great "Tow Mode", a nice low gear to get a trailer moving.
it depends upon several factors: service intervals, unequal tire sizes, tire air pressure, off-road driving. All of those will accelerate wear. If you avoid all of those issues, it should last the life of the vehicle.
You, sir, are amazing! Have just one question concerning the last part (40:00 onwards): 1) In a vehicle with a center diff, one usually has 2H (2WD), 4H and 4 Low. Therefore it's never really an AWD unless you have an extra Auto mode. Therefore, here, in your demonstration, a 2H, 4H, 4L vehicle with a center diff, won't the vehicle either be a 2WD or a 4WD (be it in 4H or 4L) but never an AWD? If yes, then why have a center diff anyway if it functions exactly like a regular tcase here? I think, the center diff allows the front and rear axles to rotate at different speeds in 4H. For example, that is how it is in the Ford Ranger/Endeavour and the LDV D90. Or am I missing something here? Please note that we will not talk about locking diffs at all. :)
As far as i can see the car is always sending power to all wheels. It does not look like it is possible to decouple the front or back wheels, so they are no longer connected to engine power. If you get stuck and the front or rear wheels are just spinning without traction, there is an option to lock front and back to get free. The front and back is then unlocked again to have a smoother ride, when locking is no longer needed.
depends on the T-case but for this example there are the following modes: 2wd 4-Hi 4-Lo AWD Neutral AWD is the only mode that utilizes the center Dif, the other modes lock it in place.
Great video! Nice to see the physical components in operation, nothing beats seeing the real thing. Can you explain why there is a neutral function for the transfer case? As the regular transmission also has a neutral, this has always seemed a little redundant to me, and even could contribute to "operator errors". thanks!
Its so the vehicle can be towed on all 4 wheels behind an RV...the issue is not all transfer cases can be done this way from what I understand, even with a neutral position you have to have a way for the fluid in the transfer case to lubricated the internal moving parts, some have an oil pump in them that is operated when the rear output shaft is spinning, but not all of them have this.
Hello,how do vacuum lines on the transfer case and transmission box influence the performance of the 4 wd operation on a Pajero installed with a 4m40 engine? How does it all tie into the 4 wd ECU and solenoid in the engine compartment and the clutch at the front diff?
When discussing the synchronizer of the 4wd engagement, wouldn't the chain and front drive shaft yoke already be spinning from being driven by the front wheels? Unless you have unlocking hubs the entire front drivetrain is being rotated by the front wheels therefore the synchronizer itself does not have to get that entire assembly up to input shaft rotational speed.
As far as I know every vehicle does that now, with the exception on the HD Fords which still have manual locking hubs. Every other 4wd has a front drivetrain that is always spinning with exception to the axle disconnect models from Jeep and the IFS GM's from the 90's.
Leaving the front axle engaged and spinning the front driveshaft decreases fuel economy about 3 mpg. Even RAM HD and Ford Super Duty disconnect the front axle now. GM and Toyota have done it for 30 years.
Really? The last 3 Jeeps I have had and the 04 Grand Cherokee I currently have does NOT disconnect the front drivetrain, nor is there any way to disconnect it, the entire front drivetrain spins as long as the front wheels do. Nor did the 04 Ram 1500 I owned. My work '14 F350 has manual hubs stock, the truck does not disconnect the axle, the driver does via the hubs. Try pulling a transfer case lever into 4wd from 2wd with the front hubs disconnected at speed and see what happens. I'll save you the trouble, it won't shift unless the hubs are engaged and the front drivetrain is spinning via the wheels. There is no way a syncro can get the entire mass of the front axle spinning up to speed in the time needed to complete a shift at any speed at all.
Sure it can, GM and Toyota have done it for 30 years. Dodge and RAM trucks did not redesign their front solid axles with an electric disconnect until some time in the past few years. Ford SD is the same way. With that system the transfer case spins up the front driveshaft and ring and pinion gear and then engages the front axle. It is not magic, but it does take a good double cone or triple cone synchronizer. Older models with manual hubs act as you described. The older Grand Cherokee and other Chrysler products just left the front axle internals spinning at all times. Horrible fuel economy, but quick to shift into 4WD. I hope that helps.
Hi, great video as always. I've always been a bit curious about these AWDs that can be locked into traditional 4WD. Is there really that much of a traction difference? Would that just be useful for slow speeds or taking off from a very slippery surface?
E Urban Hi, there is not much of a difference in traction. the difference lies in the ability of the vehicle to turn corners without the entire drivetrain binding up (as traditional 4WD vehicles do). Thanks for watching!
There might be one that just bolts onto the tail of the transmmission/ transfer case... I know for sure that there is a small system that bolts onto the back output shaft that add an extra gear to your set up and will give you a better overdrive gear while on the highway.... Its basically a 2 speed transmission, effectively giving you a "high and low" without going into 4x4--- except really its a "high and higher" gear set up .. lol.. I forget what its called-- I'll link it if I can find it.
Actually it wasn't a viscous coupler in the Selec-Trac found in the grand cherokee and cherokee, its a similar planetary gear set shown in the 2nd portion of this video. The viscous coupler was in the full time 4WD grand cherokee with the NP247 which was the quadra-trac or quadra-drive 4WD systems...both used the same exact transfer case, only difference was the quadra-drive added front and rear limited slip differentials. The selec-trac was a mechanical setup where the NP247 was a fluid coupler (viscous coupler) that allowed for power to be transferred to the front at varying amounts through that coupler. The selec-trac NP/NV 242J, 242D, and 242HD transfer cases all had the additional planetary gear set which is why they are more sought after to replace the NP/NV 247 transfer cases due to the viscous coupler failures that happen as those transfer cases wear out the viscous coupler failing causes the full time transfer case to now become a part time 4WD unit as those viscous couplers fail in a locked mode giving you 4WD but no longer able to allow for different axle speeds.
Hello, professor Thank you for your useful information Can we install the 1GR engine transfer case in the 2UZ engine? Because my car is 4 wheel drive full time And we want to convert transfer into 4 wheel drive part time From a technical point of view, it is possible or not because of the control switches and its cables And also the size of the input shaft of the gearbox My car is a 2004 4Runner and it has 8 cylinders It has only 4 H and 4 L And I want to add 2 H in its option
I think what matters more than the engine is the transmission. You will need to find out what transfer cases and/or which transmissions you're dealing with. You likely will not want to install a different transfer case from factory, because they are all electronically controlled. If the tcase is different it vwill not be electronically compatible.
Nice video. Good quality camera too! Great focus at all times, even up close... I wish everyone had this setup when trying to make "instructional" or "how to" videos on RUclips!... Anyway, I have a question in relation to all of this info... I have a 1991 Subaru Legacy AWD wagon with the *manual* transmission, and I was wondering what kind of center differential it has in it, (or even if it has one at all), because it doesn't seem to behave like your demonstration one here, in that when I have the car up on jackstands or a vehicle lift, and when I have the transmission in neutral I can turn either both front wheels or both rear wheels at the same time, and the other axle, (rear or front, respectively), turns at the same speed and *in the same direction*, (not opposite directions as you show here)... Also, on the other hand, if I put the transmission in gear and try to turn both of either the front or rear wheels together, I can't turn them at all, (they are apparently both locked to the engine)... So my car seems to behave like a standard 4WD transfer case with both front and rear axles locked together, rather than an AWD transfer case with the center diff. , as you show here... Even though my car says that it is AWD, (not 4WD), and it doesn't have any issues with "bucking" or "jumping" when turning left or right... I can't seem to find any real detailed technical info about how it works either, but I would love to know, if you know anything about the first generation AWD Legacy's from the early 90's with the manual transmission... I've heard that the manual and automatic transmissions have slightly different AWD systems associated with them, and that the manual transmission ones are much better/more capable off road... I won't disagree, because I've only managed to get stuck ONCE in the 20+ years I've owned this car, and that was just because I got high-centered in a really deep mud bog with some muddy ruts that were dug out by lifted Jeeps and trucks!... Anyway, any info or explanation that you have would be helpful and appreciated! Thanks!
Hi, Subaru AWD is similar, but the center differential, front driveshaft, and front axle are all contained in the transmission case. Their center differential is controlled by a clutch pack or a viscous clutch to limit the amount of torque delivered to the rear axle. The clutch pack allows the center differential to totally lockup like a 4 wheel drive or slip a little bit when turning corners or on different traction surfaces. I hope to get my hands on a Subaru transmission and shoot a video on its operation in the future. I hope that helps.
WeberAuto Yeah, that video would be cool to see, especially if you got one of the older manual shift AWD ones like I have in my car! Then I could see exactly why it works so well... I know Subaru has continually advertised their "Symmetrical AWD", which splits the torque evenly between the front and rear 50/50%, at least on the manual transmission cars... Not so sure about the newer ones or the automatic transmission ones, as I've heard they are different... But I will keep an eye out for your video on Subaru AWD transmissions... Maybe even get an older manual transmission one like mine and a newer automatic transmission one to do a side by side comparison with?!... I subscribed to your channel so I won't miss it whenever you get to it. BTW, I also like how clean and organized your garage/shop is behind you in your videos... That is a good sign that you're not gonna misplace a bolt or "forget" something when working on/re-assembling a car! Lol.
John, If you will take Subaru's transfer case, take the most intelligent one from STI - equipped with a both of LSD (clutch) + electromagnetic clutch (called as DCCD system) which does allow to variate the distribution between rear and front shafts manually or electronically... Very interesting to see that as it is instead of diagrams etc... You making a perfect practical video lessons, thanks!!!
I feel like changing career and learn to be a mechanic from this mister. He explains it so well and im so impressed
I've spent many years working on cars and trucks and tractors of various sizes and ages so I know my way around machinery. This was a wonderful find. I'm having issues with wife's 4x4. I watched many transfer case videos. They claim to show you how it works, wrong, they just show you the basic internal parts with no explanation, totally worthless in my opinion. This video was excellent at making how it works understandable. Thank you for producing it. I also subscribed because I saw other videos you produced that look very interesting.
This type of videos are pure gold for society. Good job and keep the nice work!
This video is one of the best out there along with those of the channel "engineering explained". As an wngineering student it really helped me understand what was actually going on inside those systems. I COULD NOT FIND any good videos to accurately and correctly explain the exaxt thing, how a tranfer case with a torsen works. This video is my savior.
Thank you!
@@WeberAuto i also have a few queations to ask about these and othe video you ve made about understanding differentials. Im trying to built my car and im trying to make the wright choises amd also explore all the possibilities.
Computer models and animations are great and all that but having an actual physical representation of what you're describing right there in front of you is, in my opinion, the best way to teach.
Thank you
Your explanation always fulfills more than an eight course meal. I appriciate your work and efforts that you put in to make complex things as easy as ABC. You started with a simple TX Case and then took it to center diffs. Reminding the viewers about the 4WD expirience of locking wheels if engaged on paved surface. Thank you very much for such a nice explanation.
I just want to take a minute of time to say thank you for your excellent educational videos, I was in the first class of GM's ASEP program in '84 and its been a while since I wrenched on a car, the last 8 years I've been working on big trucks and MRAP(Mine Resistant Ambush Protected) tactical vehicles in Iraq, Afghanistan and Qatar and now am applying for an automotive technicians job in Iraq that requires ASE certs, your videos have been invaluable to me it's amazing how much I've forgotten hahaha thank you again for YOUR time
Thank you! I was an ASEP student myself in 88. I am glad the videos are helpful. Best wishes
Very well explained. Even someone like me with no mechanical knowledge whatsoever is now able to understand the differences between part-time 4WD and AWD.
You are a good teacher. Your explanations and examples mesh like a set of well ground gears.
I appreciate that!
These videos are fantastic. If only the manufacturers would describe their equipment in this detail. Thank you sir!
Glad you like them! Thanks for watching!
I forgot to thank you for a MUCH MUCH BETTER than a shop manual description of how this system works!
This is great. I never fully understood the difference between my Jeep and Silverado's 4WD systems. Now I do. Thank you for making this video. 📚
Great teardown! I've always been curious what the lockable Torsen center diff in my V8 4runner looks like and how it works.
One small correction though. Torsen (or or more generally torque biasing differentials) are *not* speed sensitive. They don't care how fast one side is spinning versus the other. They are "torque sensing" (thus the brand Tor-sen), or more generally "torque biasing" which means they are simply a torque multiplier. An open diff always sends the same torque to both sides of the diff (seriously). A torque biasing diff (TBD) uses the angled teeth on the worm style gears to multiply the torque of the low traction (low load) side and send more torque to the higher traction (higher load) side. If an open diff always has a torque bias ratio (TBR) of 1:1, a TBD might have a TBR of say 2:1 so if the low traction side will hold X lb-ft of torque before it slips, the TBD will send 2X lb-ft to the high traction side.
Of course the flaw is that we have zero traction on one side then zero times 2 is still zero, and you get zero torque to both sides of the diff (no matter how fast one side is spinning relative to the other). And that is in fact the case. You can still get stuck with only one tire off the ground at one end of the vehicle (ask any Humvee owner). That is why this type of center diff still needs a locking mechanism for extreme low or zero traction situations.
And Torsen is not a predecessor (or substitute) for brake driven stability or brake driven "diff locking" (really brake driven torque transfer).. My V8 4Runner has a center Torsen diff + brake driven yaw stability control + A-TRAC (their name for brake driven diff locking). When the center diff manual lock is engaged, they disable stability control, but keep A-TRAC. It all works very well together even for pretty extreme rock crawling. Newer vehicles don't use Torsen center diffs simply because it's cheaper. The brakes have to do more work to achieve a similar result, but it's used so rarely it wins in the cost/benefit calculation.
I have a quastion for you , the uploader of the video, or anyone that might know. I have a audi q5 with a tosrsen. Torsen obviously doesnt lock. Audi has an edl system to simulate lock using the torsen. However, since the 4runner, landcruiser, l200, use this type of locker(torsen with a tranfer case), could i add that compoment to my audi. Im not talking about the planatary gears for the low range, but just the locking function.
@@loukasantoniou8054 I doubt that it could be added. . And unless you intend to go rock crawling with your Q5 I doubt that it's really needed either.
Man. That center differential is a sweet piece of hardware.
Excellent teacher as always Prof Kelly and an understable way of teaching
Thank you very much
@@WeberAuto You, sir, are amazing! Have just one question concerning the last part (40:00 onwards):
1) In a vehicle with a center diff, one usually has 2H (2WD), 4H and 4 Low. Therefore it's never really an AWD unless you have an extra Auto mode. Therefore, here, in your demonstration, a 2H, 4H, 4L vehicle with a center diff, won't the vehicle either be a 2WD or a 4WD (be it in 4H or 4L) but never an AWD? If yes, then why have a center diff anyway if it functions exactly like a regular tcase here?
I think, the center diff allows the front and rear axles to rotate at different speeds in 4H. For example, that is how it is in the Ford Ranger/Endeavour and the LDV D90. Or am I missing something here? Please note that we will not talk about locking diffs at all. :)
@@RealAutoReviews There are many center differential transfer cases with AWD on GM and RAM trucks and SUVs. They function differently than a traditional transfer case because they have a computer-controlled clutch pack that limits the difference in speed between the front and rear driveshafts.
@@WeberAuto awesome! One last question for the day: An AWD vehicle cannot have JUST a clutch pack, right? I mean, there has to be a differential or a traditional transfercase with it. A standalone clutch pack would do nothing, right?
@@RealAutoReviews There are AWD transfer cases with just a computer-controlled clutch pack, no center diff, but still has a drive gear, chain, and driven gear to deliver power to the front output shaft. The New Process 136 is a 1-speed example. The NP 236 and 246 are two-speed examples
Sir, thank you very much! I have been wondering all about this for a while, and you are the only one who could explain. Not only that, but you explained very well. Thank you!
Took some time to find your video with a more detailed explanation of these mechanisms. There are lots that explain the basics that I already knew. Mainly I wanted to know exactly what changes inside my NP242 (2001 Grand Cherokee 4.0) that gives it part time 4WD and fulltime 4WD. I had envisioned a setup with side gears and pinion gears that somehow locks for part time operation. Also watched your other video explaining cross over AWD. WOW...I'll stick with the relatively basic Jeep that doesn't even have locking hubs to fail even if it is a bit of a gas guzzler. Great job explaining. Thank you!!
PS: I really like the idea of using worm gears to create a limited slip in the Torsen differential. Brilliant.
I'm studing for ase. it is nice to have the visual. I think of your videos when im in the middle of a question.
Thank you soo mch.
+cesar lopez Thank you!
Being a planetary centre diff, does this create a torque bias between front and rear axles? Love your videos.....nothing like it out there. Can NOT believe you only have 69k subscribers......I would have expected to see another 0 on the end of that! Thanks for the content....great to see this depth of knowledge and practical demonstration shared for free.
Yes, a variable torque bias depending upon the rear-to-front driveshaft speed differential. Typically as much as 70-80% to the rear dependent upon the gear ratio of the planetary gear set.
Which car or truck models have the center differential transfer case shown in the second part of this video? As I understand, this transfer case supports both 2x4 and all-wheel drive on dry pavement. But for some reason, most truck and SUV manufacturers use either partial 4WD (shown in the first part of this video) or full-time AWD (that does not allow disconnecting the front wheels and drive in 2x4 RWD mode). For example, 2024 Toyota Tacoma lineup has 2x4, 4WD without center differential and one AWD trims (the AWD being Limited one), but no 4WD with a center differential. What is the reason for that - cost optimization, complexity, market segmentation?
Thank you for the video and helping a number of people who want learn and understand . God bless.
If only there were more folks like him on the internet, people would be able to have skills...
Thank you!
Best video on differentials I’ve seen
My absolute respectful salute, sir! Your work is just terrific!
Some say he's a finely tuned machined, and can communicate with intelligent life on many planets.
All we know is he's Jack Nicholsons articulated teaching Stig!
(You are a bloody fine teacher John)
Thank you very much!
You videos are so informative it's god sent. I think it helps me understanding what is causing the loud bang when my 3rd gen 4runner disengage from 4WD.
I prefer watching this than computer animated videos. This is more in detail for me.
This is fantastic. At 28:40, you mention the 4Runner transmission is an older style. I have that transmission in my 04 V8 AWD 4Runner, and the vehicle has both vehicle stability control and traction control. It doesn't pulse the brakes front and back, but does pulse the brakes for VSC . Putting it in 4WD turns off VSC, though as the vehicle has open front and rear differentials, the traction control will still pulse the brakes to help each axle find traction. Thought you'd like to know a bit more about the vehicle that transmission is out of.
Great information, thank you!
@@WeberAuto I should also mention when VSC kicks in it kills the engine power, so you don't end up with an unbraked wheel taking all the engine torque.
this is the content that I've been looking for all this time ... how is it different from the way ordinary 4WD works and how all wheel drive works.
thank you for the information
Hi John , although this isn't trade related for me ; and I had different certification , and refresher courses in a life time , this was precise , and enjoyable !.. Great watching !
Toyota Landcruiser and Lexus LX570/GX460 use both a Torsen center differential AND electronic traction control to moderate wheel spin. Belt and suspenders. Center diff is also lockable and two range in all three models.
I could watch and learn 24/7 ,, So informative.. Thank you. ....(although i think you could do with another set of hands)
Thank you very much
Thank you for the video. I've always wondered how a center differential transfer case worked
Glad it was helpful!
Thank you sir,
Everything is just perfect in teaching and videos resolution etc
Perfect teacher i ever seen.
Thanks alot
Thank you very much
Thank you for such an incredibly informative video series. Utterly brilliant!
Thank you!
Does a 2005 Pontiac Vibe all wheel drive rear differential interchange with a 2003 Pontiac Vibe all wheel drive
You Sir
Are a Master mechanic thank you for the explanation and demonstration of these gear sets
Don’t know why but this stuff always calms me down 👍
Thank you for another great explanation video. I always learn a lot with your videos.
Thank you!
Great video. As Nima someh mentioned in a previous comment, I'd also love to see a video on the Subaru STI center differential. The DCCD used on the WRX STI is very advanced, so a video demonstrating its lock up characteristics, asymmetrical torque split, and mechanical/electromagnetic limited slip capabilities would be awesome. Thanks!
+Cory Engel Thank you, I will shoot a video as soon as I can get my hands on the hard parts.
+WeberAuto Awesome, thank you, I look forward to it!!
I never thought I would understand this...but your video really helped. Thank you.
What a truly clear and helpful video. Many thanks
this guy is fantastic, needed to comment on it
+ITotallyLoveClocks Thank you very much!
Thank you for that great illustration
Hello! It's fantastic overview of transfer cases! I learned a lot from it. Thanks.
Thank you!
Your classroom looks awsome . well set up
Thanks so much!
Awesome video! Very Explanatory!
Thank you
I friggen love this guy.
Thanks!! Very clear and smart explanation.
14:40 ... actually, as long as your front lockers are locked in, that "chain gear" will be pushed by the front wheels--- so actually, it will be practically syncronized already by the front and rear wheels spinning at the same speed (given that your tires are the same size and you DO have the front wheels locked in)--- I suppose that if you 'don't have your manual wheel lockers locked in, then the syncro would have to spin that entire front drivetrain in order to shift into 4x4 (as you said)--- but in that scenario, your 4x4 wouldn't work anyway without stopping and locking in the front wheels....... I guess as little as you need to shift into 4x4 on the fly, that syncro wear from having to spin that entire front drive train just to shift smoothly, would not be too excessive. (just thinking out loud,... Great presentation as always. I have a 2002 7.3 diesel F350-- with the manual transfer case, manual locking hubs-- and 6spd manual ZF650 transmission (i believe thats what its called)--- I haven't fully checked yet, but I hope you have a video on that transfer case, i want to see what is inside of it-- whether it has a chain or direct gear drive........... I actually pulled my 6spd manual trans out of this truck and pulled it all apart and put in new syncornizers.. lol.. lets just say, it was a learning experience and I had to build my own 2 foot puller with some 3/4 inch all thread and some steel I welded up--- I could have bought this puller but it was $500, so I just made my own... I also had to make my own press, that I rigged up with a 32 ton bottle jack. I'm definitely fascinated by transmissions. Love the channel.
Spot on! I was going to write the same thing, but found your comment first. Nice to see someone who understands what he's talking about.
Does it bug you when everyone says a locked differential "sends equal torque to both wheels" or "equal power to both wheels"? Because you probably understand that an open differential sends equal torque to both wheels and a locked differential sends equal motion to both wheels.
I've also always wondered why people say 2WD mode is more efficient than 4WD when they don't have wheel lockers and all the shafts are always spinning, regardless. I'm talking about AWD cars like the Honda CR-V with its hydraulic pump system to engage rear drive when a speed differential is detected, or the Toyota Sienna with clutch packs sending power back. I mean, the rear axle and driveshaft are always spinning anyway. Is it really that they've just avoided having to add a center differential by keeping the rear disengaged most of the time? The full time 4WD system in my GX470 with Torsen center differential should be equally efficient, just cost more due to mechanical complexity, right?
Also, sweet truck! I think that's pretty much my dream truck, but so hard to find.
Excellent demonstration!!
Thank you
Wait, isn't that forward gear set already spinning with the moving front wheels? Having it in 2WD just prevents power being added to the front diff, but that doesn't actually mean it's stopped when not engaged while the vehicle is moving.
On some models, yes, on others no. Thanks for watching
Exactly
Thank you Guru for your teaching.
Around 15:00 you say that the output shaft for the fwd is statonery and so the sync has tot do a really good job. But is that the case? I think the output fwd is rotating in direct relation to the forward wheels ( but there is no torque coming from the engine ) and so the speed difference might not be that high. That would only happen if while driving in 2wd the rear wheels start to spin and the driver would want to engage 4wd (on the fly). But then again the speed difference would not be that high ( slip generally occurs in lower gears ) and the torque needed to sync fwd and rwd is not that high since the rear wheels are sliping in the first place. Correct? That is not to say the sync mechanism does not need to be sturdy.
excellent teacher, thank you...
This demonstration makes it sound like the High/Low planetary gear has something to do with the 2WD/4WD function, but it is 2 separate systems.
You can drive in 2WD low no problem mechanically because it is 2 separate functions.
Those worm-like planetary gear things in the Torsen C Type Differential, look like the things that compress air in a supercharger, a special type of impeller which tries to increase the psi of the air, but a spooler, a type of impeller in a turbocharger, causes air to get spooled in big radiuses of psi compressed out of the exhaust.
I will stay with my regular 4WD transfer case. The AWD is confusing, but you rely on the ABS to stop the "open differential wheel spin" which then allows power to the non spinning axle, be it front or rear. The other problem with the AWD is tire circumference with the Torzen (spelling) center diff assembly. If one tire was older or somehow smaller in circumference it would cause problems in the drivetrain. Check out iATN in their older case studies. GM mini vans had this problem. Destroyed transfer cases and/or differentials would happen. By having the ABS slow the spinning tire, the non slipping axle would take over and the center diff xfer case would handle it.
Lovely solid parts on that part-time transfer case.
16:10 Wouldn't there only be a couple 100 rpm difference at most though? Since the 4wd gear is already spinning at roughly the same speed since its connected to the front diff which is being turned by the road/wheels
Yes on some AWD systems, no on others. If the front differential is also disconnected for the 2WD mode, the ring and pinion are stopped.
Your explanation of the operation of the gears and clutches and sliders in the transfer case is very interesting. There is however a mistake you are making when talking about the synchros in the transfer case. The chain and front output shaft is always turning when the vehicle is in motion so that you can do shift on the fly. They parts are being driven by the front axle turning the front propeller shaft so they do not have to be spun up to speed to match. If you had a set of Warn hubs on the vehicle and they were unlocked then the shaft would not be turning and that would prevent you from having shift on the fly anyway.
Thanks for your feedback! It depends upon the vehicle and what mode of the transfer case is selected. If it is only an AWD vehicle, then I agree with you, but if it is multimode with a 2WD option, the front axle can disconnect on some models. Hubs are old school, there are actuators that can disengage and engage the front axle as you drive.
How is the front axle going to disconnect if the only connection to the front axle is through the drive shaft and the differential and the solid hubs? My Jeep Liberty is not AWD but has a 242 transfer case (centre differential) with no locking hubs so it runs all the time as do all the other standard current 4x4's that I have seen. If you do have "actuators" (locking hubs) then I would agree with you.
Newer design axles use actuators (not automatic hubs) to disconnect or connect the right or left axle shaft from the differential side gears as you drive. The actuator is located just outside of the differential housing. Disconnecting the axle shaft(s) allows the front ring and pinion gear to stop rotating. This allows for less frictional drag on the vehicle and improved fuel economy. Old school vehicles like the Jeep Wrangler, Liberty, Dodge trucks, Durango, etc do not disconnect the front axle shafts unless they have hubs. This forces the front ring and pinion to constantly rotate and drive the front driveshaft at the same time. Even the new solid axle RAM trucks use an actuator to disconnect the right axle shaft from the differential so the front driveshaft will stop rotating while driving in 2WD. I hope that helps.
Do you have any videos that cover the clutch disc engagement for 4WD used on the BorgWarner 44 and 48 series transfer cases used on Ram 1500s and the MP 3020 transfer cases used on many Jeep products. Do they have wear problems? Do they effectively act as a differential? Do their electronics require specific tire sizes (seems to be programmed for BW 44-44). Do they provide driver control of transfer case locking (at least for the BW transfer cases the answer seems to be no).
Hi proffessor , could you plese explain also the Opertion mechanisms of center differential with viscous coupling and locking CD which is used in Mitsubishi Super select transmission , to me CD powers 2 output shaft front and rear axle , operaton
This was excellent, thank you
So... the 2013 Tundra has no option to select N on the transfer case yet in theory, it’s TC is mechanically capable of such... why no ability to select this position? Would be nice to be able to flat tow. Maybe not with a Tundra but the 4runner or Tacoma would be nice to be able to pull behind an RV.
BEST VIDEO EVER!!!!
Theoretically in the open (full slip) case, tire grip all around, awd mode, that planetary type diff will split torque front to rear unequally based on the lenght of arm (radius) that the input uses (acts upon). Say it enters via the carrier, it'll give more torque to the outside ring vs to the sungear. It looked like it entered through the outside ring here. Can you please clarify where it enters and what end gets more torque in this case?
If I remember correctly, the input is on the ring gear. The rear output is connected to the sun gear, the front output is connected to the planet carrier.
Thank you so much for your videos. You go into great detail on everything and you explain every move and operation. I am actually having troubles with a nv5600 right now and am going to have to rebuild it but there is not one video or decent book out there to read and rebuild it. If you have any suggestions for me please do so. Thank you again.
spartan1071 Hi, the NV5600 is a very heavy, huge, cast iron, heavy-duty, transmission. You must have a strong transmission jack to even remove it. It also requires several special tools to disassemble and reassemble properly. We no longer have that transmission here at our school, so I can't help you with a video. The only trucks that used it (to my knowledge) were Dodge trucks. The Chrysler Training Tenters had a very good book for the theory of operation and overhaul procedures back when that transmission came out in the late 1990's. You might check on eBay to see if you can find one there. Best wishes.
WeberAuto yes I know I own that truck you speak of. It's a dodge ram 3500 Cummins. The transmission weighs in at 450lbs. Without the transfer case connected. I do heavy a very large transmission jack rated for two tons. I almost every till known to man. But thank you for the info I will definitely try to find the book you speak of. If you think of anything else please let me know.
Love it if u did the Jeep Cherokee front wheel drive system two transfer cases primary drive
For the t-case, typically all newer trucks run synthetic gear oil front & rear, many still run dino in front… I believe the auto shift engages the diff first to prevent smokin the synchro in case. The weight of gear oil is what it is regardless of syn or dino based & 75/90 ain’t much different than 80/90.
Keep em coming!!! Great stuff!
Thank you!
One doubt teacher, in this kind of differential front wheel to rear wheel differential ratio is not equal to one. I mean when the power input shaft is locked. If above ratio is not one, dose it mean there is a power distribution happen with the same ratio?
Do the planetary gears have to timed in bw4485 transfer case?
On most truck manuals, it is mentioned not to exceed certain speed when driving in 4-low. Why is that? what can go wrong if driving in 4-low at higher speeds (let us say 30-40 MPH) (Please note I am referring to driving in soft sand, as in desert safari)?
The engine rpm can get too high and damage the engine.
That is well noted and thank you for your reply and the extremely informative video.
But putting the engine aside, any extra wear or tear to transfer case or other transmission parts at higher speeds in 4low?
No, it should be fine
Due to the added gear reduction, you just run out of gears in low range. The additional gear reduction in low range makes it easier to break things as well if you aren't careful.
Any particular reason I can't use the low range of the transfer case in 2WD and/or as a gear splitter? That would make a great "Tow Mode", a nice low gear to get a trailer moving.
Samniss Arandeen Many years ago you could; I do not know why that range is prevented in 2WD.
You can with manual locking hubs
@@WeberAuto Supposedly it is to prevent the extra torque from low range, from twisting the drive shaft.
Great video! Excelent explanation! the only gear you have to stop is LOW? The rest gears are shift on the fly (Bronce Syncro natch in out Right?
At 25:00 is this a type-c torsen?
Does the torsens wear with time?
There is no Type-c torsen, there must be a misunderstanding. Yes, they wear over time.
I have found this
torsen.com/how-it-works/
At how many miles approximately can we expect to wear and need replacement or service?
it depends upon several factors: service intervals, unequal tire sizes, tire air pressure, off-road driving. All of those will accelerate wear. If you avoid all of those issues, it should last the life of the vehicle.
Thank you
Excellent video. Great tools as visual aides.
The best teacher
AWSOME class
Thank you
You, sir, are amazing! Have just one question concerning the last part (40:00 onwards):
1) In a vehicle with a center diff, one usually has 2H (2WD), 4H and 4 Low. Therefore it's never really an AWD unless you have an extra Auto mode. Therefore, here, in your demonstration, a 2H, 4H, 4L vehicle with a center diff, won't the vehicle either be a 2WD or a 4WD (be it in 4H or 4L) but never an AWD? If yes, then why have a center diff anyway if it functions exactly like a regular tcase here?
I think, the center diff allows the front and rear axles to rotate at different speeds in 4H. For example, that is how it is in the Ford Ranger/Endeavour and the LDV D90. Or am I missing something here? Please note that we will not talk about locking diffs at all. :)
As far as i can see the car is always sending power to all wheels.
It does not look like it is possible to decouple the front or back wheels, so they are no longer connected to engine power.
If you get stuck and the front or rear wheels are just spinning without traction, there is an option to lock front and back to get free.
The front and back is then unlocked again to have a smoother ride, when locking is no longer needed.
depends on the T-case but for this example there are the following modes:
2wd
4-Hi
4-Lo
AWD
Neutral
AWD is the only mode that utilizes the center Dif, the other modes lock it in place.
thank you to share like this knowledge
Thanks for watching
Brilliant. Thanks a lot!
Great video! Nice to see the physical components in operation, nothing beats seeing the real thing. Can you explain why there is a neutral function for the transfer case? As the regular transmission also has a neutral, this has always seemed a little redundant to me, and even could contribute to "operator errors". thanks!
Thank you! Neutral is there for those who want to tow the vehicle behind a motor home, etc.
Its so the vehicle can be towed on all 4 wheels behind an RV...the issue is not all transfer cases can be done this way from what I understand, even with a neutral position you have to have a way for the fluid in the transfer case to lubricated the internal moving parts, some have an oil pump in them that is operated when the rear output shaft is spinning, but not all of them have this.
Hello,how do vacuum lines on the transfer case and transmission box influence the performance of the 4 wd operation on a Pajero installed with a 4m40 engine? How does it all tie into the 4 wd ECU and solenoid in the engine compartment and the clutch at the front diff?
Great teacher
Thank you!
sir,I think the sun gear of the differential should be connected to the front output shaft
When discussing the synchronizer of the 4wd engagement, wouldn't the chain and front drive shaft yoke already be spinning from being driven by the front wheels? Unless you have unlocking hubs the entire front drivetrain is being rotated by the front wheels therefore the synchronizer itself does not have to get that entire assembly up to input shaft rotational speed.
True, but almost no vehicle does that except on old Dodges. The operation as I described is for almost all other brands.
As far as I know every vehicle does that now, with the exception on the HD Fords which still have manual locking hubs. Every other 4wd has a front drivetrain that is always spinning with exception to the axle disconnect models from Jeep and the IFS GM's from the 90's.
Leaving the front axle engaged and spinning the front driveshaft decreases fuel economy about 3 mpg. Even RAM HD and Ford Super Duty disconnect the front axle now. GM and Toyota have done it for 30 years.
Really? The last 3 Jeeps I have had and the 04 Grand Cherokee I currently have does NOT disconnect the front drivetrain, nor is there any way to disconnect it, the entire front drivetrain spins as long as the front wheels do. Nor did the 04 Ram 1500 I owned. My work '14 F350 has manual hubs stock, the truck does not disconnect the axle, the driver does via the hubs. Try pulling a transfer case lever into 4wd from 2wd with the front hubs disconnected at speed and see what happens. I'll save you the trouble, it won't shift unless the hubs are engaged and the front drivetrain is spinning via the wheels. There is no way a syncro can get the entire mass of the front axle spinning up to speed in the time needed to complete a shift at any speed at all.
Sure it can, GM and Toyota have done it for 30 years. Dodge and RAM trucks did not redesign their front solid axles with an electric disconnect until some time in the past few years. Ford SD is the same way. With that system the transfer case spins up the front driveshaft and ring and pinion gear and then engages the front axle. It is not magic, but it does take a good double cone or triple cone synchronizer. Older models with manual hubs act as you described. The older Grand Cherokee and other Chrysler products just left the front axle internals spinning at all times. Horrible fuel economy, but quick to shift into 4WD. I hope that helps.
Hi, great video as always. I've always been a bit curious about these AWDs that can be locked into traditional 4WD. Is there really that much of a traction difference? Would that just be useful for slow speeds or taking off from a very slippery surface?
E Urban Hi, there is not much of a difference in traction. the difference lies in the ability of the vehicle to turn corners without the entire drivetrain binding up (as traditional 4WD vehicles do). Thanks for watching!
Thank you very much for the education.
I kinda wish that there was a center differential available for my F250.
There might be one that just bolts onto the tail of the transmmission/ transfer case... I know for sure that there is a small system that bolts onto the back output shaft that add an extra gear to your set up and will give you a better overdrive gear while on the highway.... Its basically a 2 speed transmission, effectively giving you a "high and low" without going into 4x4--- except really its a "high and higher" gear set up .. lol.. I forget what its called-- I'll link it if I can find it.
ruclips.net/video/vjZ9JjXG5Hc/видео.html
ruclips.net/video/Vr6kLoMIrmc/видео.html
ruclips.net/video/mEhgAIVEWX4/видео.html
What about the Jeep SelecTrac transfer case used in the 2001 grand cherokee?
+ForzaMotorsportManiac1984 It was a selectable AWD center differential transfer case with a viscous coupling, similar to the Mitsubishi system.
Actually it wasn't a viscous coupler in the Selec-Trac found in the grand cherokee and cherokee, its a similar planetary gear set shown in the 2nd portion of this video. The viscous coupler was in the full time 4WD grand cherokee with the NP247 which was the quadra-trac or quadra-drive 4WD systems...both used the same exact transfer case, only difference was the quadra-drive added front and rear limited slip differentials.
The selec-trac was a mechanical setup where the NP247 was a fluid coupler (viscous coupler) that allowed for power to be transferred to the front at varying amounts through that coupler.
The selec-trac NP/NV 242J, 242D, and 242HD transfer cases all had the additional planetary gear set which is why they are more sought after to replace the NP/NV 247 transfer cases due to the viscous coupler failures that happen as those transfer cases wear out the viscous coupler failing causes the full time transfer case to now become a part time 4WD unit as those viscous couplers fail in a locked mode giving you 4WD but no longer able to allow for different axle speeds.
Hello, professor
Thank you for your useful information
Can we install the 1GR engine transfer case in the 2UZ engine?
Because my car is 4 wheel drive full time
And we want to convert transfer into 4 wheel drive part time
From a technical point of view, it is possible or not because of the control switches and its cables
And also the size of the input shaft of the gearbox
My car is a 2004 4Runner and it has 8 cylinders
It has only 4 H and 4 L
And I want to add 2 H in its option
I think what matters more than the engine is the transmission. You will need to find out what transfer cases and/or which transmissions you're dealing with.
You likely will not want to install a different transfer case from factory, because they are all electronically controlled. If the tcase is different it vwill not be electronically compatible.
Hello thank for excellent ejucation
Nice video. Good quality camera too! Great focus at all times, even up close... I wish everyone had this setup when trying to make "instructional" or "how to" videos on RUclips!... Anyway, I have a question in relation to all of this info...
I have a 1991 Subaru Legacy AWD wagon with the *manual* transmission, and I was wondering what kind of center differential it has in it, (or even if it has one at all), because it doesn't seem to behave like your demonstration one here, in that when I have the car up on jackstands or a vehicle lift, and when I have the transmission in neutral I can turn either both front wheels or both rear wheels at the same time, and the other axle, (rear or front, respectively), turns at the same speed and *in the same direction*, (not opposite directions as you show here)... Also, on the other hand, if I put the transmission in gear and try to turn both of either the front or rear wheels together, I can't turn them at all, (they are apparently both locked to the engine)... So my car seems to behave like a standard 4WD transfer case with both front and rear axles locked together, rather than an AWD transfer case with the center diff. , as you show here... Even though my car says that it is AWD, (not 4WD), and it doesn't have any issues with "bucking" or "jumping" when turning left or right... I can't seem to find any real detailed technical info about how it works either, but I would love to know, if you know anything about the first generation AWD Legacy's from the early 90's with the manual transmission... I've heard that the manual and automatic transmissions have slightly different AWD systems associated with them, and that the manual transmission ones are much better/more capable off road... I won't disagree, because I've only managed to get stuck ONCE in the 20+ years I've owned this car, and that was just because I got high-centered in a really deep mud bog with some muddy ruts that were dug out by lifted Jeeps and trucks!... Anyway, any info or explanation that you have would be helpful and appreciated! Thanks!
Hi, Subaru AWD is similar, but the center differential, front driveshaft, and front axle are all contained in the transmission case. Their center differential is controlled by a clutch pack or a viscous clutch to limit the amount of torque delivered to the rear axle. The clutch pack allows the center differential to totally lockup like a 4 wheel drive or slip a little bit when turning corners or on different traction surfaces. I hope to get my hands on a Subaru transmission and shoot a video on its operation in the future. I hope that helps.
WeberAuto
Yeah, that video would be cool to see, especially if you got one of the older manual shift AWD ones like I have in my car! Then I could see exactly why it works so well... I know Subaru has continually advertised their "Symmetrical AWD", which splits the torque evenly between the front and rear 50/50%, at least on the manual transmission cars... Not so sure about the newer ones or the automatic transmission ones, as I've heard they are different... But I will keep an eye out for your video on Subaru AWD transmissions... Maybe even get an older manual transmission one like mine and a newer automatic transmission one to do a side by side comparison with?!... I subscribed to your channel so I won't miss it whenever you get to it.
BTW, I also like how clean and organized your garage/shop is behind you in your videos... That is a good sign that you're not gonna misplace a bolt or "forget" something when working on/re-assembling a car! Lol.
John, If you will take Subaru's transfer case, take the most intelligent one from STI - equipped with a both of LSD (clutch) + electromagnetic clutch (called as DCCD system) which does allow to variate the distribution between rear and front shafts manually or electronically... Very interesting to see that as it is instead of diagrams etc... You making a perfect practical video lessons, thanks!!!
Excellent video very knowledgeable, sometimes you need three hands to work on transfercases
Thanks a lot men for ur time
thank you, sire, but I still have to repeat the video more times until I get it thanks
Thanks for watching
you are the best thank you so much
Thank you for making a video
Thank you!
Now I think I understand how you would implement a rear differential lock like I had on a Kubota tractor.
Is that center diff a JF3A from a sequoia?