shutzero

how difficult is this and what is involved in replacing the pinion seal. i have the seal and 2 bottles of the gm synthetic gear lubricant

fleetmgr

Not difficult at all with what you have unless you don't want the diff to drain out the front. If that bothers you, then you'll need a new cover gasket too, so you can drain it out the back. You'll also need a socket big enough to fit the companion flange nut, and some method of holding the companion flange. Also a torque wrench to put it back together, and a new crush sleeve to go behind the front pinion bearing.

shutzero

whats the companion flange nut and what do people do to hold the companion flange? also do you know the size of the flange nut?

fleetmgr

The companion flange is what the rear u-joint rides in on the rear end. IIRC, that nut is 1 1/8, 1 1/4...something like that.

You can hold it with a good sized pipe wrench.

shutzero

i think i have like a 30mm would that do the trick?

fleetmgr

It might, you'll have to check it.

shutzero

so other than that its pretty easy? do you know the torque specs on the flange nut? and about how much fluid is lost from doing it out of the front

fleetmgr

No harder than changing any other seal. You'll have to look the torque spec up, I don't remember what it is. You'll lose most all of the oil in the process.

946spdz

iTrader: (19)

You really needa new crush sleeve when you do it?

96capricemgr

iTrader: (1)

Technically to do it right the differential should come out of the housing so you can set the drag on the pinion bearings. There is NOT a torque spec on that nut, you tighten it till you get I believe 15-25in.lbs of drag on the pinion with used bearings. Takes a HUGE amount of force to do this with a new crush sleeve like 250-300ft.lbs.

I have heard of marking the nut and pinion and just retightening to there or slightly further, I have never tried that though.

fleetmgr

To do it right, yes. The sleeve sets the preload on the pinion bearings. And 96 hit the nail on the head for the part I couldn't remember. You have to measure the rotational torque of the whole pinion gear, not just the nut. So, he's right...the carrier should come out of the housing. The hardest part of this is finding a torque wrench small enough to measure the running torque. I've got a little 1/4" drive guy that I picked up from a bicycle repair shop IIRC.

duh

iTrader: (16)

I'm going to sound like a hack, but.....us an impact gun, then no large pipe is required you can hold the pinion yoke with your hand. DO NOT touch anything but the seal. don't pry against the pinion or anything but the housing. Gently install the new seal, and reinstall the yoke and nut. Let the impact hit it once or twice, not under full steam....then check rotational torque. If you do this you "shouldn't" need a new crush sleeve. I can't tell you how many times I've done this and not had any issues. If you're careful you can do this in about an hour to an hour and a half. just my .02

shutzero

sounds like the impact might be the way to go. i kind have have a weak gun/compressor...hopefully itll do the trick