Rear Axle / Diff. Fluid Change ?

[cujo8]

I would like to change the fluid in my rear axle this weekend and I have a few questions about this process. First off I have a 2006 GMC Sierra Z71 K1500 that has a G80 axle w/ 3.42 gears.

Questions:

1. Is this a 8.6, 9.75, 10.5, or some other size axle? I'm guessing I need to know this to get the right gasket.

 

2. Do you really have to buy all new cover bolts after you remove them and if so what are the p/n for the bolts (can I just buy 10 bolts of the proper size and grade)?

 

3. Manual calls for 75W-90 Synthetic Axle fluid, what gear oil do you folks recommend.

 

4. Will 3 quarts of gear oil be enough to get the job done?

 

5. Who makes the best gasket for this application? P/N?

 

Thanks.

[Bish]

Can't help you with PN's but you have an 8.6 rear. No need to replace bolts. I soak and clean them and loctite upon installation but I have never replaced them. 3 qts is enough for the rear. Pay attention if yours is full below the fill hole. It should have a tag with the spec. I use Mobil1 or Amsoil front and rear. GM gasket. Put gasket adhesive on one side and oil the other and you will be able to reuse the gasket in the future.