This job was a major pain. 9/10 difficulty for me. I probably had the diff/pinion out at least 10 times (thank goodness for setup bearings). I few tips for those who attempt this and have never done it... Be careful with the ABS reluctor ring (next to the ring gear) as it is very fragile and I had to get a new one from GMpartsdirect $17+shipping. Also, order the GM slip additive from them as well as its only $6. The first bottle I purchased was $16 at the local dealer Autozone had a bearing race installer kit loaner tool, which was handy for punching in the pinion races. Getting the carrier bearings out was a disaster without the proper puller. I ended up using a cutoff wheel grinder VERY CAREFULLY to get them off.

The RAtech master kit that I got from summit sucked. It was missing the pinion seal for starters. I had to grind out the ID of the pinion shims because after I would install pinion it would taper my shims and give funny backlash/contact patterns. The smallest carrier shim was .010, would have liked a couple .005. Came with crush sleeve, the nut was different than stock, I should have bought the spacer/shim kit (more later).

Stock shims were- pinion .027, L carrier .233, R carrier .245. Ended with- pinion .025, L carrier .235, R carrier .237. Backlash set at .007. Pattern was not EXACT but close as I could get it. I also had to go to napa to get a new crush sleeve because at one point I set too tight.

Drove 25 city miles- no whines/howls/hums. Got on the freeway and at 35miles I hear a slight whine at 60 with 3% throttle only. Get it back home and pinion nut loosened 1/32 of a turn (dam nut). Tightened it back up and went for 150mile drive. Nut has not moved again. Still has a slight whine from 50-70mph in 6th but only with 3% throttle. I'll call it good.

I found this page pretty useful:
http://www.pirate4x4.com/articles/te...sta/Gear_Setup

When I wanted gears I figured $250 + my labor should get it done... wrong! Figure in gears/install kit $280, fluid 4qts/2 additives (500mi change) $50, ABSring (my bad)/seal(not my fault)/rtv/brake cleaner/loctite $50, PCMtuneforless (for speedo) $190. This job costs me almost $600.

On the positive side, car pulls stronger for sure (would have went 4.10s but this car see's 50% highway). I don't have to worry about a shop doing it wrong, I can only blame myself if it fails. Although frustrating, it was nice to learn and get over the hump of being scared of doing gears.

Hope this helps someone that was in my shoes. I'll post more when I change out the fluid at 500mi.

James

 

Congrats. You just finished the hardest mod a diy guy can do to a 4th gen imo.

JD

 

500mi update- Whine still there, but i just ignore it now. It hasn't got any louder, and changing the fluid didn't change the pitch at all. Definatly a good idea to change the fluid at this time, lots of metal debris. No leaks from case cover (i used red RTV with no gasket) or the pinion seal (original leaked). Kind of wish I had gone with 4.10s now, but oh well. If this rear breaks, I'm saving up for a 12 bolt.