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8 3/4 yoke questions

KENTON

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Do all 8 3/4s use the same yoke? and is anything to know about changing the yoke? I want to switch mine to the bigger U joint, It's 1965 with a 3:91 sure grip in a 741 case.
 
No, there are at least four. Fine spline, large and small u-joint, and coarse spline, large and small u-joint. I suspect there are also different lengths. And then there are billet aftermarket versions for high horsepower apps.
Edit: coarse or fine spline pinion gear shafts.
 
The number of splines on the pinion shaft determines which yoke fine or course spline other than that you can fit any size yoke on it never heard of any difference in length the course spline is only 10 splines so it's easy to tell the difference
 
Yup...one is 10 spline and the other is like 144,000 both large and small u-joint :D
 
Thanks for the quick answers. I'll have to take the old one of to see what I have.

Is there a torque spec to reinstall? or any tricks at that point?
 
I don't think any 741's had a course or 10 spline.
 
Cranky would know better than me, but i think the 741/742 cases used a spacer, the 489 case uses a crush sleeve, which becomes a problem when changing yokes, the crush sleeve is no longer crushed.
You will need something to keep the yoke from turning, there is LOTS of torque on that pinion nut! Put in a new pinion seal, others on here can advise on torqing the nut for reassembly.
 
Anytime anyone here needs rearend help, they are almost always referred to Dr Diff. Great guy, knows mopars, always helpful.
 
The 42 uses a spacer with shims and the 41 has no spacer but uses shims too. The crush sleeve can be 'reused' but not recommended by the factory but I've done it many times. Yes, it's already crushed but there's still some 'spring' in it. You just can't go and shower down on it with a huge butt impact. Instead, use smaller one and 'sneak' up on it or do it manually and test the amount of torque it takes to turn it. I just do it by 'butt' feel....uh and feel. But BEFORE you take the pinion nut off and with the tires off of the rear end (of course taking the front tires off won't help you with anything), turn the yoke (yolk?) by hand and get a feel of how hard it is to turn. You might even mark the nut to the yoke and the yoke to the pinion once the nut is removed (recommended for reference) and get it back to where the marks align. If you don't put the yoke back on the splines in the exact some position where it came off, the marks are meaningless. Also recommended is a good dab or red Loc-Tite on the threads.
 
The 42 uses a spacer with shims and the 41 has no spacer but uses shims too. The crush sleeve can be 'reused' but not recommended by the factory but I've done it many times. Yes, it's already crushed but there's still some 'spring' in it. You just can't go and shower down on it with a huge butt impact. Instead, use smaller one and 'sneak' up on it or do it manually and test the amount of torque it takes to turn it. I just do it by 'butt' feel....uh and feel. But BEFORE you take the pinion nut off and with the tires off of the rear end (of course taking the front tires off won't help you with anything), turn the yoke (yolk?) by hand and get a feel of how hard it is to turn. You might even mark the nut to the yoke and the yoke to the pinion once the nut is removed (recommended for reference) and get it back to where the marks align. If you don't put the yoke back on the splines in the exact some position where it came off, the marks are meaningless. Also recommended is a good dab or red Loc-Tite on the threads.
Cranky you sure you don't have the spacer in housings backward? My 742 no spacer.
 
Yup......backasswards!! Hey, getting old sucks and that's my story and I'm stickin to it! :D
 
3 U-joints used in the 1960’s:
*7260 small
*7290 large
*1330 67-67 hemi and 67 440 RT & GTX.
440 C-bodies.
67-68 imperial used a u-bolt yoke not bolts and straps. The give away is clips on outside of caps like Ford and GM’s
 
Thought all the Imps got demoed!! :( JK JK but way too many got used up until they got outlawed.
 
As for reusing the crush sleeves. I just install a small shim on the top and re-crush. On the street; It has never failed me.
And if you're picky, you can buy a crush-sleeve eliminator kit.
 
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