Pinion Bearings

[CamaroCracka]

I'm getting a whine on acceleration with my ZL1 diff. Can I just take it apart and replace the pinion bearings and put it back together with the old crush sleeve or does the rear need to be completely rebuilt with new gears etc.

The yoke does seem to rotate more than I would expect before it engages the teeth, but there does not seem to be any lateral or front to back play.

[bottletalk]

sounds like your crush sleeve moved or it was pressed with too much preload.
if your gears are good just get new bearings and seals but you should dial it in and make sure it's still in spec......while ur at it you should think about going with a spacer instead of that crush sleeve.
how many ft/lbs to spin the pinion?

[CamaroCracka]

I'll have to check the ft. lbs. This is a factory diff. I'm trying to figure out if I need to rebuild it or if I (or someone who has done it before) can just change the bearings and put it back together.

[bottletalk]

Originally Posted by CamaroCracka

I'll have to check the ft. lbs. This is a factory diff. I'm trying to figure out if I need to rebuild it or if I (or someone who has done it before) can just change the bearings and put it back together.

for just replacing the bearings the crush sleeve has to be set with the proper preload on the pinion bearing and the ring should still be checked for backlash. if it was set right the last time, the gears have no wear and the bearings are the exact size it should be alright but readjusting to get a proper mesh&backlash for used gears isn't right..
u should swap the ring & pinion since your in there, taking shortcuts are just delaying the inevitable

[CamaroCracka]

I actually have a kit on the shelf as well as factory gears, but I was not wanting to pull the trigger on that since I want to use the Nitro Torsen carrier. I was just going to bandaid it until I could get that done. I think I will fill it with 85w140 and send it until I can build the diff the way I want.

[bottletalk]

Originally Posted by CamaroCracka

I actually have a kit on the shelf as well as factory gears, but I was not wanting to pull the trigger on that since I want to use the Nitro Torsen carrier. I was just going to bandaid it until I could get that done. I think I will fill it with 85w140 and send it until I can build the diff the way I want.

at least you'll get some practice on what's involved, you should think about ditching the crush sleeve for your future rebuild.
before u open it up try to get the ft/lbs on the pinion in both directions. curious what ur getting on it.

[oldman14ss]

you will need to recheck your pinion preload once again like the gentleman before me ditch the crush sleeve and use spacers. also you will need to check backlash. drop your fluid and run a magnet thru it and see what you find

[CamaroCracka]

Well I discovered that I did not have the correct socket to turn the pinion nut. It seemed like a 1.5 inch socket worked, but it needs to be a deep well.

[zmotorsports]

Like already mentioned, don't reuse the crush sleeve when replacing pinion bearings. I have had excellent results if only replacing a pinion seal by measuring the rotating torque with an inch/pound torque wrench, removing the pinion nut, replacing the seal and then reassembling using a new seal and setting the rotating torque back to where it was plus an inch or two of rotating torque but never once the bearings are disturbed.

That being said, if you are replacing bearings then at bare minimum replace the crush sleeve with a new one or better yet, use a crush sleeve eliminator. The shims are a much more precise and permanent way to set the rotating torque of the pinion.

[bottletalk]

pinion nut is 32mm. are u able to get the rotational load ft/lbs?
no big deal I'm curious also with what u find.

[CamaroCracka]

I don't have a 12pt 32mm and it's all back together now.

[CamaroCracka]

Well I was having some issues with knock readings on the scans and it was pulling timing, so after messing around with a bunch of stuff I finally broke down and pulled the turbo manifold. It had a crack on the inner bellows of the flex joint and I also found the rubber boost reference line to the blow off had deteriorated due to heat. I had a new bellows joint welded in and replaced the hose with silicone, put it all back together and installed an e85 setup while it was apart. Drove it about 50 miles yesterday and it ran better than it has since I broke some stuff at the track. I still need have the injectors installed and tune for E85, but I'm glad I'm not getting vibrations in 5th and 6th under acceleration any longer. I think I still have a pinion bearing going out and I may try to tackle that with a crush sleeve eliminator and new bearings when I have more time on my hands. I'm starting to think I should just take this thing apart about once a year as I always seem to find hidden issues when I do. Thanks for all the help.