First question a potential car buyer should ask themselves is "why" they want the 4WD/AWD in the first place. If the answer is wet roads or normal snowfalls in winter, then they should buy an AWD vehicle. These vehicles are more fuel efficient, they handle better, and automatically respond to slippery conditions without driver input. They can also handle unpaved roads very well. So you don't need 4WD for dirt or gravel roads that are flat and in good shape. Personally, I think this is the right choice for the vast majority of people. If driving "off road" is actually required (beach, heavy snow, muddy paths etc), then 4WD system with a transfer case and low range is the way to go. 4-LOW is not automatically included but if you're going to get 4WD then you might as well get it too. The Jeep Grand Cherokee and the Toyota 4Runner have trims with full-time 4WD which do not require driver input for everyday driving, but because they have transfer cases can be locked into 50/50 torque split and/or low range. They are very good options for people who really only need AWD most of the time, but do expect to need a more robust system sometimes.
Please consider turning off the background music when you're talking. It's hard to hear/understand what's being said when there's music playing at the same time.
Thank you for explaining this. I used to think part time was kind of like awd where it is automatic. I understand now that part time is basically 4H on any other vehicle and can't be used on road.
I had a 98 ZJ with the Selec-Trac. And what was nice about that was in Full-Time 4x4, the front and rear diffs acted as open diffs that would switch power to the wheels based on angles, pitch, etc. It was very useful on snow covered roads. However, in Part Time 4x4, all four wheels received upwards of 50% of torque from the transfer case, providing better off-road capability. This was beneficial in deep snow, muddy terrain, or off-road conditions. Regardless, mechanical 4x4 systems with a low-range will be superior off-road (not to mention, easier to maintain without the assistance of a computer). In addition, it's hard to take AWD cars off-road with their steep price tags, when you can get an old XJ like this and take it off road, and not worry about getting it dirty and dinged. I would like to see you guys show how the G80 locking rear from GM helps in off-road/low traction situations. Great video, guys!
Select Trac does not work the way that you described. Your front diff and your rear diff is also always open unless you installed a device like a true-trac or a PowerTrax locking mechanism. The "differentiation" in SelecTrac actually takes place in the transfer case and allows for slippage between the front and rear axles while the differentials in the axles allow for slippage between each side of the axle. When you put your stick into the part time position, then only the transfer case is locked and the differentials remain open. Now on QuadraDrive Jeeps with the V8 motor, the system works much differently, but even then the axles do not have locking differentials even though the mechanical system that is used distributes power equally to both sides to the axle even if one of the wheels has no traction.
Oye, this again. The difference is semantics and marketing. As I've said before there are no real distinction between "4WD" and "AWD", but there are 3 different (not 2) categories of all wheel traction. 1. Part-time - what most people call "4WD", a mechanically locked transfer case to split torque evenly and allow for 100:0 torque bias between axles. Low range is NOT a requirement of Part-time 4WD. No speed biasing between front and rear axles means that in tight turns on pavement the wheels chirp as they try and make up the difference in distances traveled by the wheels of the front axle compared to the wheels on the back. 2. Full-time - Incorporates some technology that allows for speed biasing between the front and rear axles, this could be a viscous coupling, a center differential, clutch packs, or a combination that allows for all 4 wheels to receive drive at all times without upsetting the speed biasing problem. Many of these systems allow you to lock the center coupling to turn them into, effectively, part time. 4 wheels are getting power to some degree passively and at all times. 3. On demand - systems that only apportion torque based on reactive inputs. These are typical of crossovers today where they use an existing vehicles drive layout (FWD in this case) but add a PTU (power transfer unit) with some technology to apportion torque to a rear drive module as demanded. The key here is that these systems are REACTIVE. Either sensor input, gerotor pump or other reactive control input. They solve the speed biasing issue not by means of a differential but by increasing the slip of the clutches in the PTU. The KL cherokee Trailhawk's Ecotrac Lock system is a good example of why low range isn't required to be "4WD". it's a category 3 system with a PTU and a rear drive module acting reactively to sensor inputs to either completely disconnect the rear driveline or engage it as needed. In low range the PTU and the RDM (rear drive module) both use a planetary reducer to slow the front axle and rear axle speeds down separately and a collar locks in the PTU engagement to act like part time system. In the common definition of 4WD v AWD this puts the cherokee in a confusing middle ground. if you use the 3 Category system it makes more sense. The moral of the story here is that AWD v 4WD is a red herring. The only real way to differentiate between all wheel traction systems is by categorizing the means in which they work, since one company's "symmetrical AWD" could be mechanically similar to another company's "real time 4WD". Don't buy into the marketing and over generalization of terms...they aren't descriptive enough to be valuable...look at HOW it works. I wrote up a more detailed explainer with flow diagrams here if anyone is interested in the how oppositelock.kinja.com/how-modern-4wd-systems-work-and-why-they-dont-suck-as-b-1821928762
Please note we did not produce this from “regurgitating the same bad information”. We sat down and spoke with several engineers from various auto manufacturers and other automotive journalists before producing scripting this video. There is a distinction, not a “Red Herring” as you describe.
AWESOME write-up! Many many thanks. I hate the confusion around this especially as a consumer and trust me- no one at a dealership has the slightest clue.
TFLnow the red herring refers to the false dichotomy between awd and 4wd. It means literally that comparing the two in this way is to distract from the real conversation, not necessarily from bad intent. Im sure you had all the best intentions in your research and presentation but fell into the same trap as so many others in painting distinctions based on arbitrary qualifiers that don't hold true in all cases and don't create meaningful categorical distinction. This is the regurgitated bad information... That you need "x" to be 4wd and "y" for awd. It's a common trope in automotive journalism and it doesn't dispel confusion, in perpetuates it. It's the same reason the English language is considered to be such a mess... What good are all these rules if there are exceptions to all of them? Your research was generally good regarding haldex and transfer case operation but you missed the conclusions. Again all good intention. Look, im here because you guys are the only ones doing these kinds of videos and bless you forever for doing it! There are thing you do that drive me crazy but so many things you do right so keep it up. Hopefully you'll see that my intentions are to inform, like you, and not to tear down. These topics are important to me for some reason and so it's likewise important to me people get the full picture whenever im in a place to provide it. Thanks for reading my work, btw, as this comment wouldn't exist without following my link and others once there. Hopefully you could see my passion in my work like I see in yours. Keep up the good work, but steer clear of journalistic assumptions and generalizations as it relates to technical classifacation if you can.
Thank you. I used to think I could get good information from the dealer, then I realized that most of the people employed by the dealer aren't car people, they are sales people, or finance people, etc that happen to work in the car industry. The claims I've heard from dealers....oh man.
Thanks Patrick for better insight then the boys did in the video. They should take this video down because it's done sooo poorly. And yes the people at dealerships have no idea what they are selling. As a retired ASE Master Tech freinds ask me to go car shopping, and I find it entertaining to stump salemen with tech questions. They tend to make up shit on the fly and make it clear to me they have no idea what they are selling. I even seen people plowing snow with an AWD. People need to know that is not a smart thing to do. AWD needs to stay on pavement and well groomed gravle roads. Leave the heavy lifting for 4WD
The short answer is that it's the same reason cars come with differentials - tires need to be able to rotate at different speeds as they travel different distances around corners. The front axle pair of tires travels a different distance than the rear axle pair around corners and there is no way in a part time system to account for that speed discrepancy. It's dangerous to drive and damaging to the vehicle drive on high traction surfaces without that speed biasing.
It's more of AWD with auto locking differentials. Lots of extra parts with added expense to repair... Should stick to paved roads or dealership parking lots
It is impossible to fairly compare, the jeep has taller tyres which have more bite, it has more articulation, and better off road angles, whereas the volkswagen is designed to do 70% of its life comfortably on road and then confidently traverse a muddy field, dirt track, 12inch puddles and ice. But then 4 motion is a more competent all wheel drive system that always gives power front and rear (4motion is quattro and 4 matic) and it can give power to the wheels that need it
I have a question: my Fj Cruiser have low range an high range that I can select manually but it does not give you the option to leave it on 2wd ( it’s a 6 speed manual ) so does that means is Awd because is always sending power to all 4 wheels? Or is just a regular part time 4wd?
It's permanent 4wd. Just like Hummers, Jeep Grand Cherokees, Land Cruisers and Land Rovers. Permanent 4WD is basically a 4wd system that's normally AWD instead of 2WD, but lets you lock the center differential to make it 4WD. If it didn't have a locking center diff then it would just be AWD. Examples of vehicles with AWD and low range, but no locking center diff would be some versions of the Jeep Grand Cherokee and the 2003-2006 Range Rovers. They use a limited slip center diff instead, a lot like Audis and Subarus.
My 02 Dodge Durango has AWD but it has a switch so that I can put it into 4Hi or 4Lo if I need to. So there are AWD transfer cases with low range gearing
If a vehicle has a transfer case it's 4WD. An AWD uses a clutch pack system or viscous coupling system that activates when tires lose grip and start spinning. The Durango and Grand Cherokee have a full-time 4WD system as opposed to a part-time 4WD system.
SO.... GM "officially" shanked your method of determining AWD vs. 4WD by removing the 2 speed transfer cases from all of their trucks and SUVs unless order with the Z71 package in trucks or either Z71 or Tow Package in their truck based SUVs. And I am not going to count FCA with the systems in the Cherokee Trailhawk or the Durango which smack at these methods here as well.
on the jeep isn't the part-time 4WD basically the same as AWD. Part-time 4WD doesn't have the traction control like all the better AWD but uses the same concepts. you can drive on the highway in part-time 4WD but not 4WD and definitely not in 4WD with locked differentials.
A competent driver can get an all wheel drive vehicle further than a bad driver with a proper 4x4, my 2006 porsche cayenne or 2005 touareg in my hands will go further than any wrangler or range rover if my wife was driving same thing if i was in a 2004 fiat panda i could get that further than my wife if she was in a landcruiser
but you could get further down a rouged trail in a Range-Rover than you could in a Porsche Cayenne. but on a slick road you could maintain control at higher speeds in a Porsche Cayenne than in a Range-Rover. AND you could get the Fiat stuck quicker or loose control at lower speed on a road that isn't as slick, compared to the Range-Rover or the Porsche Cayenne
TFLoffroad or the heavy duty trailer I believe. I know construction companies won't be driving gm trucks if the only way you get the 2 speed transfer case is with z71 or max trailering. Hey can you ask GM why can't I ger z71 on yukons and why the have to be butt heads and only offer z71 on lt models? Maybe I don't want leather but I want z71. I am not happy with how gm does their build/packaging of their vehicles options.
AWD means the front and rear axles can spin at different speeds and 4WD means they can't. With all the different types of systems out there that's the only consistently true statement you can make. You can't base it off having a transfer case because Subarus have transfers cases, not can you say it's having a two speed transfer case, because there are full time AWD vehicles that have two speed transfer cases. The only thing you can really say that constantly say that's stays true every time is that if you can fully lock the front and rear axles its 4wd and if you can't its AWD
First question a potential car buyer should ask themselves is "why" they want the 4WD/AWD in the first place.
If the answer is wet roads or normal snowfalls in winter, then they should buy an AWD vehicle. These vehicles are more fuel efficient, they handle better, and automatically respond to slippery conditions without driver input. They can also handle unpaved roads very well. So you don't need 4WD for dirt or gravel roads that are flat and in good shape. Personally, I think this is the right choice for the vast majority of people.
If driving "off road" is actually required (beach, heavy snow, muddy paths etc), then 4WD system with a transfer case and low range is the way to go. 4-LOW is not automatically included but if you're going to get 4WD then you might as well get it too.
The Jeep Grand Cherokee and the Toyota 4Runner have trims with full-time 4WD which do not require driver input for everyday driving, but because they have transfer cases can be locked into 50/50 torque split and/or low range. They are very good options for people who really only need AWD most of the time, but do expect to need a more robust system sometimes.
Please consider turning off the background music when you're talking. It's hard to hear/understand what's being said when there's music playing at the same time.
Sadly, this should be watched by some "car vlogger's" "reviewer's".
Thank you for explaining this. I used to think part time was kind of like awd where it is automatic. I understand now that part time is basically 4H on any other vehicle and can't be used on road.
I like both systems, but I do like Tommy's Jeep much more, it's a real 'classy' vehicle.
I had a 98 ZJ with the Selec-Trac. And what was nice about that was in Full-Time 4x4, the front and rear diffs acted as open diffs that would switch power to the wheels based on angles, pitch, etc. It was very useful on snow covered roads. However, in Part Time 4x4, all four wheels received upwards of 50% of torque from the transfer case, providing better off-road capability. This was beneficial in deep snow, muddy terrain, or off-road conditions. Regardless, mechanical 4x4 systems with a low-range will be superior off-road (not to mention, easier to maintain without the assistance of a computer). In addition, it's hard to take AWD cars off-road with their steep price tags, when you can get an old XJ like this and take it off road, and not worry about getting it dirty and dinged. I would like to see you guys show how the G80 locking rear from GM helps in off-road/low traction situations. Great video, guys!
@sreilly
Nice comment. I would also like to second the idea of demonstrating the Eaton locker. Perhaps comparing to a Ford with an "e-locker"
jcpoiuy That would be a great match.
Select Trac does not work the way that you described. Your front diff and your rear diff is also always open unless you installed a device like a true-trac or a PowerTrax locking mechanism. The "differentiation" in SelecTrac actually takes place in the transfer case and allows for slippage between the front and rear axles while the differentials in the axles allow for slippage between each side of the axle. When you put your stick into the part time position, then only the transfer case is locked and the differentials remain open. Now on QuadraDrive Jeeps with the V8 motor, the system works much differently, but even then the axles do not have locking differentials even though the mechanical system that is used distributes power equally to both sides to the axle even if one of the wheels has no traction.
Oye, this again. The difference is semantics and marketing. As I've said before there are no real distinction between "4WD" and "AWD", but there are 3 different (not 2) categories of all wheel traction.
1. Part-time - what most people call "4WD", a mechanically locked transfer case to split torque evenly and allow for 100:0 torque bias between axles. Low range is NOT a requirement of Part-time 4WD. No speed biasing between front and rear axles means that in tight turns on pavement the wheels chirp as they try and make up the difference in distances traveled by the wheels of the front axle compared to the wheels on the back.
2. Full-time - Incorporates some technology that allows for speed biasing between the front and rear axles, this could be a viscous coupling, a center differential, clutch packs, or a combination that allows for all 4 wheels to receive drive at all times without upsetting the speed biasing problem. Many of these systems allow you to lock the center coupling to turn them into, effectively, part time. 4 wheels are getting power to some degree passively and at all times.
3. On demand - systems that only apportion torque based on reactive inputs. These are typical of crossovers today where they use an existing vehicles drive layout (FWD in this case) but add a PTU (power transfer unit) with some technology to apportion torque to a rear drive module as demanded. The key here is that these systems are REACTIVE. Either sensor input, gerotor pump or other reactive control input. They solve the speed biasing issue not by means of a differential but by increasing the slip of the clutches in the PTU.
The KL cherokee Trailhawk's Ecotrac Lock system is a good example of why low range isn't required to be "4WD". it's a category 3 system with a PTU and a rear drive module acting reactively to sensor inputs to either completely disconnect the rear driveline or engage it as needed. In low range the PTU and the RDM (rear drive module) both use a planetary reducer to slow the front axle and rear axle speeds down separately and a collar locks in the PTU engagement to act like part time system. In the common definition of 4WD v AWD this puts the cherokee in a confusing middle ground. if you use the 3 Category system it makes more sense.
The moral of the story here is that AWD v 4WD is a red herring. The only real way to differentiate between all wheel traction systems is by categorizing the means in which they work, since one company's "symmetrical AWD" could be mechanically similar to another company's "real time 4WD". Don't buy into the marketing and over generalization of terms...they aren't descriptive enough to be valuable...look at HOW it works.
I wrote up a more detailed explainer with flow diagrams here if anyone is interested in the how oppositelock.kinja.com/how-modern-4wd-systems-work-and-why-they-dont-suck-as-b-1821928762
Please note we did not produce this from “regurgitating the same bad information”. We sat down and spoke with several engineers from various auto manufacturers and other automotive journalists before producing scripting this video. There is a distinction, not a “Red Herring” as you describe.
AWESOME write-up! Many many thanks. I hate the confusion around this especially as a consumer and trust me- no one at a dealership has the slightest clue.
TFLnow the red herring refers to the false dichotomy between awd and 4wd. It means literally that comparing the two in this way is to distract from the real conversation, not necessarily from bad intent. Im sure you had all the best intentions in your research and presentation but fell into the same trap as so many others in painting distinctions based on arbitrary qualifiers that don't hold true in all cases and don't create meaningful categorical distinction. This is the regurgitated bad information... That you need "x" to be 4wd and "y" for awd. It's a common trope in automotive journalism and it doesn't dispel confusion, in perpetuates it. It's the same reason the English language is considered to be such a mess... What good are all these rules if there are exceptions to all of them? Your research was generally good regarding haldex and transfer case operation but you missed the conclusions. Again all good intention. Look, im here because you guys are the only ones doing these kinds of videos and bless you forever for doing it! There are thing you do that drive me crazy but so many things you do right so keep it up. Hopefully you'll see that my intentions are to inform, like you, and not to tear down. These topics are important to me for some reason and so it's likewise important to me people get the full picture whenever im in a place to provide it. Thanks for reading my work, btw, as this comment wouldn't exist without following my link and others once there. Hopefully you could see my passion in my work like I see in yours. Keep up the good work, but steer clear of journalistic assumptions and generalizations as it relates to technical classifacation if you can.
Thank you. I used to think I could get good information from the dealer, then I realized that most of the people employed by the dealer aren't car people, they are sales people, or finance people, etc that happen to work in the car industry. The claims I've heard from dealers....oh man.
Thanks Patrick for better insight then the boys did in the video. They should take this video down because it's done sooo poorly. And yes the people at dealerships have no idea what they are selling. As a retired ASE Master Tech freinds ask me to go car shopping, and I find it entertaining to stump salemen with tech questions. They tend to make up shit on the fly and make it clear to me they have no idea what they are selling. I even seen people plowing snow with an AWD. People need to know that is not a smart thing to do. AWD needs to stay on pavement and well groomed gravle roads. Leave the heavy lifting for 4WD
You guys should’ve explained why you shouldn’t leave you’re truck in 4x4 on pavement. I’ve heard different theories/misconceptions about that
The short answer is that it's the same reason cars come with differentials - tires need to be able to rotate at different speeds as they travel different distances around corners. The front axle pair of tires travels a different distance than the rear axle pair around corners and there is no way in a part time system to account for that speed discrepancy. It's dangerous to drive and damaging to the vehicle drive on high traction surfaces without that speed biasing.
Patrick Rich 👍
Question. Which is the Best? Awd or 4x4? Maintenance cost which is cheaper?
So the question is, is Active Drive Lock (the 4WD/AWD system found on the KL cherokee) a 4x4 system, or an AWD system? It has a true low range.
It's more of AWD with auto locking differentials. Lots of extra parts with added expense to repair... Should stick to paved roads or dealership parking lots
It is impossible to fairly compare, the jeep has taller tyres which have more bite, it has more articulation, and better off road angles, whereas the volkswagen is designed to do 70% of its life comfortably on road and then confidently traverse a muddy field, dirt track, 12inch puddles and ice.
But then 4 motion is a more competent all wheel drive system that always gives power front and rear (4motion is quattro and 4 matic) and it can give power to the wheels that need it
I have a question: my Fj Cruiser have low range an high range that I can select manually but it does not give you the option to leave it on 2wd ( it’s a 6 speed manual ) so does that means is Awd because is always sending power to all 4 wheels? Or is just a regular part time 4wd?
Cristobal Arriaga Yes it is AWD
It's permanent 4wd. Just like Hummers, Jeep Grand Cherokees, Land Cruisers and Land Rovers. Permanent 4WD is basically a 4wd system that's normally AWD instead of 2WD, but lets you lock the center differential to make it 4WD. If it didn't have a locking center diff then it would just be AWD. Examples of vehicles with AWD and low range, but no locking center diff would be some versions of the Jeep Grand Cherokee and the 2003-2006 Range Rovers. They use a limited slip center diff instead, a lot like Audis and Subarus.
What year FJ is it? My brother drives a 14 model and it has 2 hi, 4hi, N and 4lo just like any other 4x4.
My 02 Dodge Durango has AWD but it has a switch so that I can put it into 4Hi or 4Lo if I need to. So there are AWD transfer cases with low range gearing
If a vehicle has a transfer case it's 4WD. An AWD uses a clutch pack system or viscous coupling system that activates when tires lose grip and start spinning. The Durango and Grand Cherokee have a full-time 4WD system as opposed to a part-time 4WD system.
I have an 04 Dodge Durango and the options are AWD, 4LOCK and 4LOW. Haven't had a chance to try it yet, though.
SO.... GM "officially" shanked your method of determining AWD vs. 4WD by removing the 2 speed transfer cases from all of their trucks and SUVs unless order with the Z71 package in trucks or either Z71 or Tow Package in their truck based SUVs.
And I am not going to count FCA with the systems in the Cherokee Trailhawk or the Durango which smack at these methods here as well.
Would like to see you guys try gold mine in 4 hi before going 4 lo. I think 4 lo is over kill for this coarse
on the jeep isn't the part-time 4WD basically the same as AWD.
Part-time 4WD doesn't have the traction control like all the better AWD but uses the same concepts.
you can drive on the highway in part-time 4WD but not 4WD and definitely not in 4WD with locked differentials.
A competent driver can get an all wheel drive vehicle further than a bad driver with a proper 4x4, my 2006 porsche cayenne or 2005 touareg in my hands will go further than any wrangler or range rover if my wife was driving same thing if i was in a 2004 fiat panda i could get that further than my wife if she was in a landcruiser
but you could get further down a rouged trail in a Range-Rover than you could in a Porsche Cayenne.
but on a slick road you could maintain control at higher speeds in a Porsche Cayenne than in a Range-Rover.
AND you could get the Fiat stuck quicker or loose control at lower speed on a road that isn't as slick, compared to the Range-Rover or the Porsche Cayenne
My word..
The new Silverado doesn't have 4 low... so is it AWD?
4LO is optional in the new Silverado...new to trucks, but not to other vehicles (Jeep Grand Cherokee springs to mind).
It is still selectable. They still call it 4wd. Sucks that low range is only an option.
jcpoiuy the new Silverado is the truck favorite of Soccer moms everywhere.
The Silverado can be purchased with or without a low range transfer case so it can be either 4WD or AWD depending on if you get the Z71 model or not.
TFLoffroad or the heavy duty trailer I believe. I know construction companies won't be driving gm trucks if the only way you get the 2 speed transfer case is with z71 or max trailering. Hey can you ask GM why can't I ger z71 on yukons and why the have to be butt heads and only offer z71 on lt models? Maybe I don't want leather but I want z71. I am not happy with how gm does their build/packaging of their vehicles options.
AWD means the front and rear axles can spin at different speeds and 4WD means they can't. With all the different types of systems out there that's the only consistently true statement you can make. You can't base it off having a transfer case because Subarus have transfers cases, not can you say it's having a two speed transfer case, because there are full time AWD vehicles that have two speed transfer cases. The only thing you can really say that constantly say that's stays true every time is that if you can fully lock the front and rear axles its 4wd and if you can't its AWD
Bedt fan
4WD lack of central differential from AWD, that's the only difference.
They all have centre differentials. In a proper 4x4 the center differential can be locked.
1st comment
Is that a 'comment?',..It sounds like a statement of fact to me!