G80 Install

[zsqure]

Has anyone ever installed a limited slip (G80) in their truck? I mean pull out the standard rear and bolt in a G80. I'd scour the boneyards for a donor vehicle. The local stealer has something close that I would be willing to trade my '02 for.

[crafty]

My truck was ordered with a locking rear but arrived at the dealer without one. My salesman called, told me about the mistake and then told me that the service department was going to order all necessary parts to change things over to a locking rearend. I've had the truck two years and all is working well. You might wish to order parts and convert it yourself! :D :D :D

[Chris N5CWM]

I installed one in my brothers ZR2 S10 4x4 pickup. Same basic procedure but it is a pain in the rear to do. I cut a finger and had to finish the job with one finger wrapped, trying not to get gear oil in it. Long story.

He found a used Eaton locker (G80) that was apparently removed from a vehicle under warranty so he got it basically free. Turns out the reason it was removed was because it didn't work! After all the work putting it in his truck, it would work better than no locker at all but it did not lock up like it should.

Take it in to a shop with a good reputation and plan on spending some $$. I am not sure what GM wants for the Eaton unit that goes in the AA rear axle but try to get it from someone that has an account with a GM parts department so you can get it a lot cheaper. Find a shop that specializes in axles and transmissions. Get a quote in writing, also showing what work they are going to do. And a limited warranty for at least 60 days or more just in case it starts to make noise.

If you want to tackle it yourself...
The hard part is shimming the ring and pinion gears for the proper gear contact so you have no noise from the gears. Buy new carrier bearings and ring gear bolts, new gear lube, gasket or permatex. Good time to put on a Mag Hytec cover!
The new carrier bearings will have to be pressed onto the new carrier with a hydraulic press. Also buy "Prussian Blue" gear dye so you can see the gear contact pattern. Just changing the carrier and using the same gears, usually results in very close specs on the gear runout but there is a chance of noise due to machining tolerances differences between the carriers. I have done a couple that were carrier changes using the same gears and ended up great, very quiet. And one Ford Crown Vic 8.8" that I changed from 2.73 open to a 3.27 posi. It went well and was quiet.

It's not easy getting the ring gear off the old carrier. The bolts that hold it on are usually reverse thread! I found out the hard way. Clockwise to loosen! Most are that way. Once it is off, and you are ready to install the ring gear on the new G80 carrier, clean it well and put it in an oven (don't tell the wife) to heat the ring gear up to like 425F for 45 minutes or so (my guess) so it expands. Clean the carrier of all grease, clean the bolt threads. Best to buy NEW ring gear bolts since they stretch when torqued. Get the correct shop manual and use a torque wrench on all bolts.

Take the ring gear out with oven mitts, place it on the carrier and start the new bolts. They should have blue loc tite on the threads if new, if not use BLUE not RED loc tite. Torque them down evenly and in sequence across from each other like you would lug nuts on a wheel. Don't tighten them to spec until the ring gear is pulled all the way down to the carrier. Do this quickly before the ring gear cools and shrinks.

It's not always that easy. Getting the carrier back in might require a case spreader. I've never changed gears in an American Axle but I know there are some different bearing caps. Looks like some kind of adjustable setup.

So I'm gonna say play it safe and buy a new G80 carrier and find a shop with a good rep to install it. :D