10.25 Pinion Bearing Preload With New Bearings

[Delly]

After having some rear end noise on my 10.25" rear, I crawled under and found that the pinion nut was loose, and the yoke had some play. I tried to just retighten the nut, but could not get the play out of the yoke.

After disassembling the rear, I found that the sleeve on the yoke was wore, and the outer pinion bearing and race were pitted. I ordered a USA Standard Gear master kit to replace all bearings while I had the differential apart.

I have the new pinion bearing races installed into the differential, and am now attempting to install the pinion and get the correct preload with the new bearings. I am using the pinion shims that came with the kit, and verified that they matched the existing shim thickness that I removed from the pinion, and have a new crush sleeve and pinion nut. Using the Ford manual for reference I should have a minimum torque of 160 ft/lb. The problem is that I go beyond the preload spec of 16 to 29 in/lb way before I even get close to 160 ft/lb.

I continually spin the pinion and tap it to verify that the new bearings are seated, but it does not help. Searching through here, it sounds like 160 ft/lb isn't even enough to crush the crush sleeve.

Could it be that the preload goes beyond spec until the sleeve is crushed, and then comes back down? Or maybe using the old shim height is not correct for my new bearings?

 

[Black dawg]

Sounds like the crush sleeve crushed to easily or is too short. Did you have a hard time getting it to crush?

 

[Delly]

I took it out and compared it to the old sleeve - the old one is definitely deformed much more than the new one. The new one still looks like it did when I got it.

 

[Booyah45828]

Could it be that the preload goes beyond spec until the sleeve is crushed, and then comes back down? Or maybe using the old shim height is not correct for my new bearings?

Not likely, the only time your preload will come down is when the bearings wear in, but they won't wear in that much.

I mean, you're technically supposed to use a depth gauge to determine your pinion depth shim thickness anytime you change bearings. Usually, if you're using good bearings, it doesn't change though. Regardless, that shim thickness should have very little to do with your issue. As black dawg said, it sounds like your crush sleeve is too short. If that's the case, the book says to throw a new crush sleeve in and try again.

As far the crush sleeve is concerned, I like to use crush sleeve eliminators if at all possible. I believe the one for a ford 9" will work for the 10.25 as well, but don't quote me on that. They're a little more work to set up, but I've never had a pinion nut loosen when using an eliminator, only with crush sleeves.

 

[Delly]

The bearings and races in the kit were Timken, so good quality. The eliminator kit sounds like something worth while...I will start looking into that, thank you.

 

[u2slow]

I second the eliminator. I feel it actually makes the setup easier.

 

[Black dawg]

If the new sleeve has not crushed as far as the old one, and the pinion bearing preload is too tight, either you have some wrong parts, or a bearing or race isnt seated all the way.

 

[Delly]

Thank you - I ordered an eliminator kit and a new pinion nut. I will re-check the races and bearings once the pinion is out again.

 

[u2slow]

When using the eliminator, assemble and check without the pinion seal - as many times as it takes. Once you're completely happy, then install the seal.

 

[Delly]

Dumb question, why install without the seal? Doesn't the eliminator go on the same location of the crush sleeve, which would already be on the pinion when it is installed in the housing?

Just asking because I already have the new seal installed, but I do have an extra one of those too.

 

[u2slow]

Because you can't guarantee you get it shimmed right the first time, and the seal adds drag when you're determining preload. Also a good chance you pop the seal out when you push the pinion through the outer bearing.

 

[Delly]

I ordered the solid spacer kit, and have it installed with the correct preload.

I have the carrier installed and checked the backlash, which is 0.006”. This is not within spec in the Ford manual (0.008 - 0.015), but is within spec for the USA Standard Gear manual but I am assuming they mean for new gears.

The gears I have are, from what I can tell, original. Would 0.006” be too tight on these old gears?

 

[Diesilee]

Years ago working with a full time mechanic, was doing as
you are and came up with .004 backlash on my '86 F350
10.25 that had 300,000 or so under it's wheels.
He said "run it", I did and now it has 500,000. No problems.

 

[Delly]

That was my thought as long as I didn’t hear any crazy noises or feel any vibrations.

 

[typ4]

keep an eye on your pinion because the crush sleeve eliminator kits that I bought needed to be chamfered where they sit on the pinion.
And I agree your backlash is fine