Anyone ever replace a differential themselves?

I have a posi (Auburn) that I am pondering putting in. I am not taking out the pinion, so all I have to set is backlash. Seems easy enough, I have the tools, with all the parts I have, I should have plenty of shims laying around.

Anyone mess with it?

I haven't actually done it but I do know that they say not to use feeler gauges. Everyone says to yellow gear marking compound?

It's some yellow stuff they put on the ring gear then turn it to see how it meshes with the pinion. They claim it's far more accurate than gauging.


I tried to paste this in but it got ugly so here's a page with what to look for.

http://www.drivetrain.com/ringpinioninstal.html

Go about half way down and you'll see the pics

I have the dial indicator to do backlash ok. But after reading the FSM, I am holding off.

1. Ring gear bolts must NOT be reused (why? are they torque to yeild?)
2. Factory shims are NOT to be reused (GM claim they will crack if reinstalled)

So I will order the parts and just do it again. I hope to reclaim most of my synthetic fluid in the diff now, but I bought some 80W90 just in case to replace it if it is low.

I am guessing the seal hardened up in the cold and isn't sealing anymore.

Posi will have to wait a few weeks... Hopefully be able to do it before first snow....

My understanding was the factory shims could crack during installation if not done carefully and with the correct tool, which is sort of punch with a half moon ring on the end to grip the shim.
I think something similar could be fabricated rather easily. I'd give it a try reusing the original shims. Others have done so successfully. If backlash and tooth contact pattern check out okay button it up and go for a ride.

On the other hand, new ring gear bolts and pinion lockbolt is standard procedure, always has been. They are definetly not torque to yield junk, however. If this is a stock 8.5 inch clutch type carrier GM has a heavy duty 300 lbs. replacement "S" spring available for around $10, can't remember the part number off hand.
Don't forget to add a bottle of GM limited-slip additive.

Actually it is a aftermarket Eaton 19559-010, I thought it was an Auburn, but it isn't (I am sooo glad!). Clutch type, 400# springs (not S type, several coils). Should do pretty good. I don't know if I will go with the 800# springs, not at least for now. Not sure if I want to play with that much chatter.

I did an install once of some used gears with original shims, didn't have an issue. I agree, the tool is critical. Without you put a stress point and it will eventually crack. I didn't break anything on 2x installs, but honestly, I didn't get to drive it, I couldn't get the crush sleeve to crush, I just couldn't put enough pressure on it.