Has anyone found a paper on all of the variations on the 8.75 rears. I cant even figure out whether the various center sections will fit my housing....and with this, several types of axles, brakes, widths and U joints. Would be nice if someone has pulled this together for us nimrods.
Rear End Education please
- Thread starter 66furys
- Start date
Be careful with axle and housing width charts off the interwebs... Most aren't correct, especially when citing C body rears.
But the question needs to be asked. What do you want to change? All the drum brake combinations are going to bolt up if that's what you want to change and ALL the center sections from 1957 to 1974 will fit. From there it's what you want... Want a sure grip? Want the stronger large or tapered pinion because you're putting a killer motor in?
This is probably as good as any other guide, but it even contradicts itself on axle widths, so remember that a tape measure would be your friend if you change housings. . https://www.hemmings.com/stories/article/mopar-8-3-4-inch-rear-ends
But the question needs to be asked. What do you want to change? All the drum brake combinations are going to bolt up if that's what you want to change and ALL the center sections from 1957 to 1974 will fit. From there it's what you want... Want a sure grip? Want the stronger large or tapered pinion because you're putting a killer motor in?
This is probably as good as any other guide, but it even contradicts itself on axle widths, so remember that a tape measure would be your friend if you change housings. . https://www.hemmings.com/stories/article/mopar-8-3-4-inch-rear-ends
I am not sure yet if I will change anything on this one. After years of drag racing in yooot, I have friends who push for at least a 3.91. And I have to admit that right now, when I launch this thing, it likes first gear for a bit instead of the shift.....and then the argument that the beasty will not like the highway. But, I do not think my current engine is going to make enough power from the 383 inches to make a difference. New carb and so on, and I am working to build up a head of steam after this thing has not been driven, other than started, for maybe 20 years...having only talked to last 3 owners. So, basically, I am trying to educate myself, and am confused on some of the basics. I consider basics the housings and the pumpkins, the splines and axle lengths, etc. Again, right now, just for fun...not for part shopping yet. Still working on the steering now. thanks
Just read the hemmings, and it is great, thanks. Answers most of my questions. And, one of the strange things on this car is that I think, under the heavy grease and grime is a 741 casting number....not too clear yet. But, am surprised about this on a 383 fury. But then, I found all the ten nuts loose as hell when under the car and housing leaking. So, maybe someone has already changed him. More work.
The_Eagles’_Nest
Well-Known Member
All 3rd members will fit on all mounting flanges of the axle housing.
There are 3 main types of 3rd members, but there are others that were for 50s cars. The main types are 841,742 and 489. The difference is the pinion gear shaft diameters. You have to order the specific ring and pinion for the specific housing you have.
There are two yoke types that are common. 7260 and 7290. The 7260 is smaller and usually found on a-bodies or slant six/small block V8 cars.
The 7290 is on B, C and E or big block V8 cars.
The housings are all different between A, B, C, D and E bodies. If I’m not mistaken 1964 is the last year for an external adjustment nut at the axle end.
There are 3 main types of 3rd members, but there are others that were for 50s cars. The main types are 841,742 and 489. The difference is the pinion gear shaft diameters. You have to order the specific ring and pinion for the specific housing you have.
There are two yoke types that are common. 7260 and 7290. The 7260 is smaller and usually found on a-bodies or slant six/small block V8 cars.
The 7290 is on B, C and E or big block V8 cars.
The housings are all different between A, B, C, D and E bodies. If I’m not mistaken 1964 is the last year for an external adjustment nut at the axle end.
Wonderful points all, thanks. When you say that the housings are different, but the third members will fit all....does this mean that there is a difference in maybe width and maybe spring shackle width....housings are different. I think, think , that my 66 has the adjustment on axle lash.....only from the tube views....have not gotten to the car yet on that. But, with the center button between the axles, I think that it may have lasted a bit longer, but not sure yet. I am amazed that chrysler used this lash for the bearings....outboard outside the seals....amazing. The new green bearing goes more modern, with a ball bearing, that will take thrust, and does not depend on the lash and clearance from for a simple single bearing outboard, instead of dual tapered bearings as on front wheels. Yes, may not take the same load as a tapered roller, but pretty good for most purposes. Finally, where in heck did you get the numbers for the yokes.....I have never seen them....Ujoint size.....no numbers, just measure them.....aaargh.
The_Eagles’_Nest
Well-Known Member
All third members will bolt in 1958 and up but that does not necessarily mean the axles will work or that the third member itself is correct.
The u-joint numbers are out there. You can find them in many places. I just happen to know them because I just finished an 8 3/4” for my Valiant.
The u-joint numbers are out there. You can find them in many places. I just happen to know them because I just finished an 8 3/4” for my Valiant.
That is why I am trying to get this understood. Seems the third members will all fit all the housings. But, the axles had both different splines, and different length.....the length is not as much discussed. And, different brakes on the newer flange axles...OK. But, interesting also that there were two yokes and joints. Very good info, thanks.
You guys are a little off base.
the 1958-1964 open centers have a 1/4“narrower width thrust block that the 1965 and newer opens and all the sire grips.
58-64 open is 1 1/4” wide.
1 1/2” on all the rest.
yes the splines for that axle shafts are the same.
Don’t forget the 1330 unjoint yoke on 66-67 Hemi, 67 440 b-body and the 67-68 imperials with u bolt yokes.
A body drum brakes for an 8.75 rear won’t interchange with anything else. And vice versa. Axle shafts don’t protrude out far enough.
the 1958-1964 open centers have a 1/4“narrower width thrust block that the 1965 and newer opens and all the sire grips.
58-64 open is 1 1/4” wide.
1 1/2” on all the rest.
yes the splines for that axle shafts are the same.
Don’t forget the 1330 unjoint yoke on 66-67 Hemi, 67 440 b-body and the 67-68 imperials with u bolt yokes.
A body drum brakes for an 8.75 rear won’t interchange with anything else. And vice versa. Axle shafts don’t protrude out far enough.
57fury440
Well-Known Member
1958 was the first year for sure grips but the 1957 center sections were 8 & 3/4 too and will fit. The 741 is plenty stong for a stock 383 with an automatic behind it. They make a universal joint that will work to join the driveshaft to a yoke on a center section with a different size. They can still be ordered at most "good" parts stores.
Is this amazing or what....this is why I asked the question....amazing. And, I never imagined a Ujoint with different sizes.....but, I will do more homework. thanks muchly. I will add that I cannot understand chrysler and these thrust block spacers.....some videos show them being placed in with magnets.....I have no idea. Why in the world do they not just organize the axle to work with the outer bearing without adjusting to an inner spacer block.....nutz. Also nutz to use a grease lubed outer bearing instead of lubed by the diff fluid.....nutz. Yes it worked, but I do not look forward to pull my axles to check the bearings in this old car.....sorry, sorry, just dont see it.
Some great info here;
www.forabodiesonly.com
An accurate 8 3/4" rear axle width list
Ok, so, I've posted parts of this list a few times, normally in response to some of the really inaccurate charts and lists that are out there and posted too frequently. It's not my list, I sourced it from the internet but I can't remember where. Since the time I downloaded it several years ago...
www.forabodiesonly.com
Blusmbl
Member
If I remember right you can measure the U-joint cap to figure out which one you have. You can also swap yokes depending on the pinion as there are 10 and 29 spline versions. There is a crush sleeve in 489 case rearends that you theoretically shouldn't swap yokes with unless you set the gears up again but I've done it before.
I have 1350 u-joints on mine but there weren't any OEM 8 3/4 rearends with that u-joint size.
I have 1350 u-joints on mine but there weren't any OEM 8 3/4 rearends with that u-joint size.
57fury440
Well-Known Member
Pulling the rear axles on the rear is easy. You slide off the brake drum and remove the 5 nuts holding in the axle and it just slides out. If you had an older model with the big nut in the center, then you would need a puller to get them out. I have run these rears for 50 plus years (including drag racing) and haven't had any problems.
Blusmbl
Member
I've hurt them, but only with 4 speeds. They're really durable behind automatics!
All good points.....but as I age, having to pull axles out to grease the bearings is boring.....and very difficult to an old guy. I did have one or two of the old mopar rear ends with the threaded axles....I did not take them apart...just the engines and transmissions. But, I will likely have to pull these for service, but am not happy about it. And I need to do more work on the ujoints.....I used to just get them by cap size, but I see all these numbers relating to size.....more work to do. thanks for the lessons.
Now, get the Mopar Performance Race Manual which pertains to rear axles. That section used to be in the older Race Manuals (over 1000 pages total), but when they split things apart in the 1990s, using normal type-set publications rather than printed, type-written formats, it might better explain some of the things, plus the "conversion u-joint" and such. Should be some rear axle spring pad widths, too, but for A- and B-bodies, as I recall. But what you're concerned with is the center section more than anything else.
The Race Manuals are Chrysler Factory Information, rather than otherwise. Ford and GM people had to read "Hot Rod" or "Car Craft", but Chrysler had "Race Manuals" with factory information, FWIW.
Just some thoughts,
CBODY67
The Race Manuals are Chrysler Factory Information, rather than otherwise. Ford and GM people had to read "Hot Rod" or "Car Craft", but Chrysler had "Race Manuals" with factory information, FWIW.
Just some thoughts,
CBODY67
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