Pinion bearing.

[Super ranger 01]

Hey guys ive got the 8.8 rear end..and i was wondering if there should be any slack or slop in the pinion shaft when the driveshaft is off...i also have the main keeper nut off to replace the pinion seal an noticed that there is some movement in the pinion shaft...thanks

 

[Bird76Mojo]

There will be some rotational "slack" - it's set up that way to give the gears the proper clearances as they rotate. It shouldn't be a huge amount though. It's typically called backlash, and it's set within a given tolerance range when installing the differential carrier and the ring/pinion gears. The differential carrier is shimmed from left/right to attain the proper backlash, as well as the pinion shaft being shimmed.

As for up/down or left/right movement, that's not a good sign.

But with the pinion nut removed, of course there will be movement.

 

[Super ranger 01]

So would u most likely say the pinion bearing is shot also?

 

[Bird76Mojo]

Hard to tell without actually seeing and feeling it. But if the pinion nut is removed, and that's where the "play" is coming from, then it's not an issue.

If there's a lot of movement up/down or left/right when everything was tightened up (before you tore it down) then yes, I'd imagine the bearing is on it's way out. Unless something wasn't tightened to spec or had came loose somehow.

 

[Super ranger 01]

Ok.thanks..ive got the bearing out an it an the race seems ok but i think since its already out..im just gona replace it...thank u again

 

[Uncle Gump]

That is really not the way you want to do that...

I would put it back together and torque the pinion nut... without the seal installed. Then inspect for movement in the pinion shaft. if OK... remove the nut and yoke... drive in the seal and torque it up.

Replacing just the outer bearing without checking the pinion bearing preload is probably going to cause you issues.

 

[Curious Hound]

^^^^ +2

There are 2 bearings on the pinion shaft. You have to remove the carrier to get the pinion out and replace the inner bearing. At that point, you are in the magical realm of "differential setup" it's not the easiest thing to do unless you have the proper tools and experience. Every bearing you replace changes the clearances in the differential. That changes pinion depth, backlash and tooth engagement patterns for the ring and pinion gears. These measurements are set using shims and torque specs. They are measured with a dial indicator, beam style torque wrench and by reading the wear pattern on the gears.

 

[adsm08]

I agree with all the above.

You can't accurately inspect for axial play on the pinion shaft with the nut off. That releases all the tension and preload that takes all that play out of the system.

 

[Super ranger 01]

I did as u said an checked it wthout the seal in it...all was ok..there was no slack in it when i torqued it...so i replaced the seal an all is back together..thanks guys for all yalls input...im a rookie at the rearend stuff...

 

[Bird76Mojo]

I hope you didn't forget to use some RTV on the pinion flange splines when you put it back together. That can be a source for a leak..



GB

 

[Super ranger 01]

I did use some