Changing the yoke in an 8 3/4

[AMXguy]

The new drop out I put in my 8 3/4 had some damage on the yoke where a U joint was lost at some time , I thought it would be OK but it's getting loose so I need to change it out.

 If I change the yoke what am I going to have to do to get it adjusted right? I've changed seals before by marking the nut anf going back to the same position with no problem, if the new yoke is excatly the same length should I be able to do the same thing? I'm hoping I don't have to pull the whole thing apart again.

[71chally416]

Just make sure you change the crush sleeve if it has one or the nut will back off. 

[AMXguy]

But if you change the crush sleeve don't you have to reset the bearing preload all over? that's what I'm trying to avoid, I think, I've always hated messing with rear end gears.

[ntstlgl1970]

is it a 489 case (crush sleeve) or 742 case (shims). If it is a 742 case, no adjustments are needed, just tighten to spec. 489 case will require setting the preload correctly with a new crush sleeve or you can try to re use it if you have the right tools to measure the current preload and are able to restore it to exactly the same preload with the new yoke.

The only way I have done this without replacing the crush sleeve (not on an 8 3/4 but it doesn't matter, the procedure is the same) is to:
1. get the car off the ground
2. pull the axles
3. pull the driveshaft
4. Measure the constant rotating torque of the pinion (not the initial) with an inch pound torque wrench.
5. Replace parts but do not tighten
6. Measure the rotating torque
7. Tighten the pinion nut to sneak up on the original measured rotating torque
8. repeat steps 6 and 7 as necessary.

If you go over the original rotating torque more than say 3-4 inch pounds, the crush sleeve will have to be replaced.

[71chally416]

I've changed them before without disassembling the rear on the 489.
I've even seen people use locktite on the nut and reuse the sleeve. Any mark you make will no longer be valid with a different Yoke that's machined differently. The trick is getting the nut tight enough with the car in the air or off the ground if you don't have the right tool to hold the yoke. I would recheck it a few times after you change it to make sure it stays tight.   

[Changin Gears]

is it a 489 case (crush sleeve) or 742 case (shims). If it is a 742 case, no adjustments are needed, just tighten to spec. 489 case will require setting the preload correctly with a new crush sleeve or you can try to re use it if you have the right tools to measure the current preload and are able to restore it to exactly the same preload with the new yoke.

The only way I have done this without replacing the crush sleeve (not on an 8 3/4 but it doesn't matter, the procedure is the same) is to:
1. get the car off the ground
2. pull the axles
3. pull the driveshaft
4. Measure the constant rotating torque of the pinion (not the initial) with an inch pound torque wrench.
5. Replace parts but do not tighten
6. Measure the rotating torque
7. Tighten the pinion nut to sneak up on the original measured rotating torque
8. repeat steps 6 and 7 as necessary.

If you go over the original rotating torque more than say 3-4 inch pounds, the crush sleeve will have to be replaced.

I agree, I have done the several times with a 489.  It is the procedure Chrysler specifies for replacing the seal with an 8.25 or 9.25 axle in later years.

[quagmire]

That's the way I do them too.  You'll need an inch pound beam type torque wrench to check it, and it needs to be a very low scale too.  I've worked with more than a few morons who just run it down with an impact and forget it.     Needless to say sometimes this comes back and bites them. 

[71chally416]

My friend did that with his 440 4 speed Dart. The first time he launched it with slicks at Atco 

[Aracer]

Mark Williams Inc. sold me some nuts that have a fiber lock that is thin enough, to fit two on the pinion with room to spare. Also a few carefully placed hammer blows to the crush sleeve when it is completely apart will stretch it enough to re-use. The reason I didn't use the new Mopar one is, it would not crush at all. 200+ ft.lbs. is a lot of force, and on the work bench it, seemed impossible and did not move.
     Conclusion: Many years and drag events have not loosened it. I am removing it now so, I will see what's, what. I will re-install the 2.76 ratio on the thin clutch (1968) posi., that I ordered for the car when I felt the gas shortage in the 1973. A 440 with this set will make a "Gumball Rally" type cuda. On the highway the low gears get annoying fast. Plus the torque of the 440 will pull the 275x15x28" tires easily. That pic. will have to be in a new thread,