What's the torque for a course spline 8 3/4? Small (1 1/8").

My 1969 Dodge factory service manual calls for 240 Ft lb minimum on both the 741 and 742 pinion nuts It calls for 170 ft lbs minumum on the tapered pinion shaft nuts

There's the problem. I have a 489 case with a course spline pinion, so it uses the small nut like the 741 case. I'm also using the crush sleeve eliminator from Dr dif. I'm thinking I'm safe at 170lbs.

Some of the eliminator kits with the a lock nut specify 150 ft. lbs.

Some times using those large torque values will result shearing the threaded stub off the pinion or just cause thread or nut failure.We suggest you make it tight enough to hold,using thread locker and after your final assembly pinch the lock nut or threads with a center punch at 90*(4 spots).

Was thinking the same thing cos my 489 29 spline pinion calls for 280 ft lbs. but I set it at a bit over 200 ft lbs. and called it good...........

How is enough to hold? My last one I used the RA tech spacer (don't want it again, its wimpy and didn't like the shims, had to file it so that it would work) which said to torque to 120 ft lbs, so thats what I did. With the red threadlocker it was tough to take apart, I had to use a good deal of heat and strength. I used a correct pinion nut also.

I bought a Yukon one this time, much beefier looking, but they don't specify a torque. I'm thinking 150 ft lbs but not sure if thats enough. 200+ is crazy, how do you guys even get them that tight, special fixture to hold the case? I can't hold everything and torque it that tight unless I installed it in the car with the parking brake on.

Huh? More info on that please.

Straight from DrDiff.............

Solid spacer? 125 - 150 with red loctite on pretty much everything. Pay attention to the turning torque. It will change as the nut is tightened, even with a spacer.

Went over to the bullet and this is what many recommended and since I have to change out my pinion anyhow, I think 150 it will be cos I got 14 in lbs at 150 and 19 at 200+.............

We use a good air impact and often check and find 150 lbs ft + to be enough.As mentioned use Locktite ,lock nut,and peen the nut or threads with a center punch.After you have sheared of a few pinions you will get my drift.

Thanks for everyone's input, but I put it together yesterday with 170, new crimped nut and it's all good to go. I hope.

Thats what I do as years ago I had a pinion nut back off and fall off driving down the road. By a streak of luck I actually found the nut on the side of the road and got it back together to drive it to my buddies station and fix it right. But I always use the red locktight and stake the pinion nut in four 90 degree places. Ron

Can you guys that peen/stake/punch the pinion nut (at 4 places) explain how to do it? I have a pinion nut that has backed off, and want to try this stake method this time, but not sure how to do it.

t

Take a center punch and place it between the threads of the pinion stem and the threads of the nut. Give it a GOOD whack. You are basically creating a pinch nut of sorts----it's far less likely to back off.

Per Mark Williams

"6) Before installing the seal it is a good idea to check the bearing preload, even with a new assembly. Install yoke or coupler on the pinion, install pinion nut and torque to 110-125 ft/lbs (if possible it is suggested to use a used pinion nut during this operation). Rotate the pinion with an inch/lbs. torque wrench. The rotational drag should be 20-25 in/lbs (if re-assembling a support with used bearings the rotational drag can be 10-15 in/lbs). If the rotational drag is too low step up the pinion nut torque in 10 ft/lbs increments and re-check the drag. Once the correct drag is achieved note the pinion nut torque. Maximum pinion nut torque is 175 ft/lbs. If the amount of drag is too high the preload spacer is too thin and should be replaced (new spacers will require machining). If rotational is low the spacer will have to be trimmed. trim in .001 steps and re-check.

7) With the bearing preload checked and/or set, remove the yoke or coupler, install the pinion seal, re-install the yoke or
coupler. Install a new pinion nut with Loctite and torque to the amount determined in step #6."

This is the Mark WIlliams information for 9". Big pinion Ford is the same except the torque numbers increase 25# or so.

Everyone has their own experience and opinion. This has worked perfectly for me for years on all rears. I very seldom go over 150# Loctite is mandatory and not just a drop. It will take a good impact and maybe some heat to get it back apart.

If this is a 489 case or any other with a crush sleeve this is NOT going to work...

I'm working on a 742. Long story is that it had a diff leak, I pulled the driveshaft out and saw the nut was loose. Cleaned threads, put red loctite, more than a dab, and torqued it to 240 ft lbs. Filled it up and no leaks.

A few weeks later, and it's leaking again. I haven't crawled under it yet, but suspect the nut has backed off again. Looking for a stronger barrier than red loctite.

It's a motive gear Ring and Pinion.