The 489 housing has an 1”7/8 pinion. The 742 housing as an 1” 5/8 pinion OK, the 742 has a large pinion bearing. I would rather have a large pinion shaft, wouldn’t you, think about it? Would you not rather have a large pinion. BIGGER is better. I am 66 and have ONLY ran the 489 diffs. From to street to hard drag racing. My only issue is the 30 spline is too small to race with. That’s my opinion everybody has one need to know the facts.❤
Hi Ron. Love your Channel!! Can you help me out. Have a 66 Belvedere with a 440. The rearend is 8/34, 489 with 3:55 gears and has to be changed because of a loud whine and banging in the rearend…sounds like someone hitting a pipe with a hammer …Want to change to 3:23 for better gas mileage and lower rpm ….Tires are 27540R17 on the rear Do you see a problem changing? Anything else needs to be changed? Any advice is appreciated Thanks Dennis
Dennis, the 489 is TOPS when it comes to mopar diffs. Reach out to Dr, Diff, Mancini, Herb parts etc For your bearing or rebuild kits and change to the posi unit if needed. Mopar or No car. Jim
Very helpful! I picked up a homebuilt post hole digger for my tractor with an unknown diff in it. I finally figured out its a Mopar rear with a 207041. It has a leaking pinion seal so need a replacement. I think the diff will be OK with 40 horse power right?..:)
So why does everyone sa489 I got a 742 489or 88 gears someone had it in a 340 400 dollars do you think the 742 with a big block will be cool 391 or 410. Gears I think the 488 or 9 would not be good for the old 440 cause you can’t rev like a 340 ?
I have a question. I have a pair of 741 case carriers. The open axle, I'm replacing with a sure grip. Do both carriers have the same axle spline counts?
M.pietro used gears often whine. You can't get the setup exactly same as when it was put together. Run 'em until they die. You'll still get 30k to 50k miles before they crap out.
Thank you for the information. I have a 73 Chrysler Imperial and I had the gears changed from 2.76 to 3.91 and a sure grip installed. The mechanic who put the parts together has plenty of experience in Mopars, however he changed the gears twice and the diff is still whining at 40 to 45mph. This whining diff is making me crazy. I’d like to change the gears again for a 3.23 and keep the sure grip. Could you assembly a diff or make it in my unit? Thank you.
Good useful info. I hate all of the domestic cone style setups. Because the carrier itself is the friction surface (outer part of the "cone"). Once it starts slipping,it's junk (unless you like "one wheel peel",lol). It can't be rebuilt like the earlier "clutch type" mentioned.
I have the 741 housing with the tapered axles and it needs the wheel bearing and I want to ask if I can use the moser bearing kit or not since Summit or Jegs can’t tell me because they both don’t know about my 64 440 rear axle.
Thank you very much for your video, I currently have a 1967 charger with the number 2070742, do you think that I do not have the correct differential for my car?
Our Valiant had a mild 360 with a 727 and 4.10 gears with a spool. It ran pretty well with an 11.66 @ 113 mph being it's best ET and MPH on 9" wide slicks. That car won more money bracket racing than we had invested in it.
hi,,,i just purchased a 471 with sure grip 3.55 at the swap meet. i have a 489 non posi 3.23 in my Roadrunner...will the sure grip go into the 489? and id like to add a 4.10 gear set...hoping i didnt make a $700 mistake. at one time i was a wiz at this stuff but i stop doing the car thing and got old lol
Yes, the Sure Grip units are interchangeable between the 741, 742 and 489 cases. Take care and adjust the gear backlash correctly and you will be golden. If you are switching to 4.10 gears and have never done this before, have a professional do it for you as it is not for the faint of heart and requires experience and specialized tools.
Ron , please get in touch with me ...... I need a replacement rear end for my 67 440-4-speed GTX . My rear end has a top speed of 70 mph with the rear end that is in it . On the interstate It sounds and feels like I'm going to bust a transmission at 70 mph because of the low low gearing . Can you help me please ?
@@mostlyoldparts Ive had several 4-speeds in my 63 years , but never a car that is geared as low as this one is . I'm going to get the numbers of the rear end and see what it says this weekend .
Is there any way to identify the gear ratio from the outside without pulling the pan off ? I know you could Jack up the rear end put a chalk mark on the drive shaft and differential , mark the tire , turn the drive shaft and count how many times it spins in relation to the revolution of the tire and get a darn close idea of the ratio that way … but just curious if there’s any stamps / tags or markings on the exterior of the differential that would provide the precise information that matches the stamp on the ring gear internally.
From the factory, Chrysler affixed a metal tag to one of the studs securing the center section to the housing with the gear ratio embossed in the tag. Typically, if the center section has been removed for service, the tag is not re-installed. Also, the factory included a stamped circular tag to one of the same studs that read "Use Sure Grip Lube" if the unit was equipped with a limited slip differential. Other than the stamped tags, there is no way to outwardly identify the center section as to which gear ratio it has or as to whether or not said unit is equipped with a Sure Grip differential. With no tags, the ONLY way to know for certain is to remove the center section and inspect it.
@@mostlyoldparts Hey thanks for the feedback ! Well that raises another question. If Chrysler specifies to use “ sure grip lube “ on a limited slip differential, does this imply that it has a friction modifier in it ? I have a 86 Dodge Ram D150 2WD with a 318 and it has a tow package which included the heavy duty 727A transmission ( loadflite ) I just recently acquired this truck and I’m going through everything and changing fluids etc . Just don’t know if it requires a friction modifier / additive for the differential or not
The 489 housing has an 1”7/8 pinion. The 742 housing as an 1” 5/8 pinion OK, the 742 has a large pinion bearing. I would rather have a large pinion shaft, wouldn’t you, think about it? Would you not rather have a large pinion. BIGGER is better. I am 66 and have ONLY ran the 489 diffs. From to street to hard drag racing. My only issue is the 30 spline is too small to race with. That’s my opinion everybody has one need to know the facts.❤
Hi Ron. Love your Channel!! Can you help me out. Have a 66 Belvedere with a 440. The rearend is 8/34, 489 with 3:55 gears and has to be changed because of a loud whine and banging in the rearend…sounds like someone hitting a pipe with a hammer …Want to change to 3:23 for better gas mileage and lower rpm ….Tires are 27540R17 on the rear
Do you see a problem changing? Anything else needs to be changed? Any advice is appreciated
Thanks Dennis
Dennis, the 489 is TOPS when it comes to mopar diffs. Reach out to Dr, Diff, Mancini, Herb parts etc For your bearing or rebuild kits and change to the posi unit if needed. Mopar or No car. Jim
Very helpful! I picked up a homebuilt post hole digger for my tractor with an unknown diff in it. I finally figured out its a Mopar rear with a 207041. It has a leaking pinion seal so need a replacement. I think the diff will be OK with 40 horse power right?..:)
SORRY , The biggest Has the biggest pinon shaft ! Almost all 741 were were non sure grip , many 742 were sure grip. The 489 is the newest model1
Great video, addition info: The cone carrier uses a larger inner bearing than the clutch carrier.
So why does everyone sa489 I got a 742 489or 88 gears someone had it in a 340 400 dollars do you think the 742 with a big block will be cool 391 or 410. Gears I think the 488 or 9 would not be good for the old 440 cause you can’t rev like a 340 ?
Thanks Ron and please keep the videos coming. Love the Road Runner too.
I have a 742 peg leg with 2.76 gears, I always heard the 489 was the better of the three.
Great short intro to these diffs. I always thought the 489 was supposed to be the most desirable.
Isn’t the 489 the strongest?????????????
YES!!!!!!!!!!!!! SIR!!!!!!!’
@@jmr1970 I like your reply. I guess my mutiple ???’s was funny. Thanks for your reply. :)
I got me one of each! 741, 742 and 489. They make lovely planters.
They make even better door stops and boat anchors. :)
"the last FOUR digits are 489" ?????
I like your new channel, good info
i need a dana 60 4 my road runner
got83/4
You can also figure the exact date the ring gear was made its to the right of the ratio. I bet you knew that. Just additional info
Great info . Glad you started this YT channel. Thanks again.
STAY REAL!
I have a question. I have a pair of 741 case carriers. The open axle, I'm replacing with a sure grip. Do both carriers have the same axle spline counts?
If they are stock, yes
@@mostlyoldparts Thank you!👍
thanks for another quick and informative video.
The old Valliant!👍🏼🏆
Thank you Sir
Will the pinion interchange for the 742 to the 741
No, They are different diameters and utilize different bearings.
The 741 is an 1 1/2 pinion and the 742 is an 1 5/8 pinion
Good video 👍
Good Job! I switched gearsets and now I'm looking for a used 29-spline yoke for a 489. I have a 10-spline I don't need. Thx!
I have to say ‘Thanks’ for a very informative 5 minute video. Nice Job! 👍
I grabbed a 741 3.23 and 489 2.76 loose in the junkyard the other week, open units, getting a 742 next!
M.pietro used gears often whine. You can't get the setup exactly same as when it was put together. Run 'em until they die. You'll still get 30k to 50k miles before they crap out.
Thank you so much for the information. I am refurbishing a 1966 Plymouth Satelite.
I thought the 489 was the strongest , guess I was wrong .
They are!
The only downfall to the 489 case is the use of the crush sleeve. If you replace the sleeve with a spacer and shims, they can be hella strong.
Thank you for the information. I have a 73 Chrysler Imperial and I had the gears changed from 2.76 to 3.91 and a sure grip installed. The mechanic who put the parts together has plenty of experience in Mopars, however he changed the gears twice and the diff is still whining at 40 to 45mph. This whining diff is making me crazy. I’d like to change the gears again for a 3.23 and keep the sure grip. Could you assembly a diff or make it in my unit? Thank you.
Good useful info. I hate all of the domestic cone style setups. Because the carrier itself is the friction surface (outer part of the "cone"). Once it starts slipping,it's junk (unless you like "one wheel peel",lol). It can't be rebuilt like the earlier "clutch type" mentioned.
Thanks much for this video very informative!👍✝️
Awesome presentation...thanks for sharing!
Have a 742 clutch type sure grip with 4.11 gears in my charger.
Good stuff. Happy Motoring.
Very informative video Ron! I’m gonna check mine out! What’s the difference between dana posi sure grip or limited slip?
The name. :)
Good information to have. Any thoughts on finding an 8 3/4 for an a body that has a 8 1/4 in it now?
I have the 741 housing with the tapered axles and it needs the wheel bearing and I want to ask if I can use the moser bearing kit or not since Summit or Jegs can’t tell me because they both don’t know about my 64 440 rear axle.
I don't believe there is a green bearing kit for the tapered axles. Check with Moser, Strange, Summers Brothers, etc. regarding this.
Thank you very much for your video, I currently have a 1967 charger with the number 2070742, do you think that I do not have the correct differential for my car?
The 742 case is correct for a 67
Will the front u joint yoke from my 489 work on a 742? Thanks
If it has the same amount of splines, yes.
62 Valiant race car? I currently own a pair of 62 Valiants. One stock 225 push-button, other stuffed with a 440. Both are a lot of fun.
Our Valiant had a mild 360 with a 727 and 4.10 gears with a spool. It ran pretty well with an 11.66 @ 113 mph being it's best ET and MPH on 9" wide slicks. That car won more money bracket racing than we had invested in it.
Good video and info
🚒👍
Great video
hi,,,i just purchased a 471 with sure grip 3.55 at the swap meet. i have a 489 non posi 3.23 in my Roadrunner...will the sure grip go into the 489? and id like to add a 4.10 gear set...hoping i didnt make a $700 mistake. at one time i was a wiz at this stuff but i stop doing the car thing and got old lol
Yes, the Sure Grip units are interchangeable between the 741, 742 and 489 cases. Take care and adjust the gear backlash correctly and you will be golden. If you are switching to 4.10 gears and have never done this before, have a professional do it for you as it is not for the faint of heart and requires experience and specialized tools.
@@mostlyoldparts great info thank you
Ron , please get in touch with me ...... I need a replacement rear end for my 67 440-4-speed GTX . My rear end has a top speed of 70 mph with the rear end that is in it . On the interstate It sounds and feels like I'm going to bust a transmission at 70 mph because of the low low gearing . Can you help me please ?
Sounds like you need a taller tire and some 3.54 gears in that GTX
@@mostlyoldparts Ive had several 4-speeds in my 63 years , but never a car that is geared as low as this one is . I'm going to get the numbers of the rear end and see what it says this weekend .
Thanks, found out mine is a 741 case , and most likely 3.73 gears.
To small of pinion 1 1/2…
New subscriber good stuff maybe later on do a video on how to know if it's a 8 3/4 or an 8 1/4 etc.
The 8-3/4" has a removable carrier as shown. The 8-1/4" does not.
Is there any way to identify the gear ratio from the outside without pulling the pan off ? I know you could Jack up the rear end put a chalk mark on the drive shaft and differential , mark the tire , turn the drive shaft and count how many times it spins in relation to the revolution of the tire and get a darn close idea of the ratio that way … but just curious if there’s any stamps / tags or markings on the exterior of the differential that would provide the precise information that matches the stamp on the ring gear internally.
From the factory, Chrysler affixed a metal tag to one of the studs securing the center section to the housing with the gear ratio embossed in the tag. Typically, if the center section has been removed for service, the tag is not re-installed. Also, the factory included a stamped circular tag to one of the same studs that read "Use Sure Grip Lube" if the unit was equipped with a limited slip differential. Other than the stamped tags, there is no way to outwardly identify the center section as to which gear ratio it has or as to whether or not said unit is equipped with a Sure Grip differential. With no tags, the ONLY way to know for certain is to remove the center section and inspect it.
@@mostlyoldparts Hey thanks for the feedback !
Well that raises another question. If Chrysler specifies to use “ sure grip lube “ on a limited slip differential, does this imply that it has a friction modifier in it ? I have a 86 Dodge Ram D150 2WD with a 318 and it has a tow package which included the heavy duty 727A transmission ( loadflite )
I just recently acquired this truck and I’m going through everything and changing fluids etc . Just don’t know if it requires a friction modifier / additive for the differential or not
😎👍👌✌🖖😁
742 was until 69
All the 69 units I've seen have been 489s, but I'm sure Chysler probably had scads of 742s left over from previous years they had to get rid of.
Excellent video, cleared everything up in 5 min.
Thanks, now I have a clue at the swap meets
Great video thank you !🙏🏼