Or you can go with this

 

I bought Pennzoil Gearplus 80W 90 and it says a limited slip top treatment is not needed or recommended. Also says on the bottle that it is made for limited slip, mt1 and conventional diffs. Should I still use the Additive? Thanks for any help.

 

Nope, it already includes the additive. Good to go.

 

Just went through this and ran into some beginner type issues. Stuff that makes sense after.

Use the frame rails for the jackstands. I initially used the axles to support and of course, under weight the diff is pushed up behind the fuel tank where it's very space is very restricted to reach the top nuts.

Lift high enough that your tires can spin so that when you clean the gears you can reposition and clean the ones that were initially facing away from you.

Have a light.... its dark and you can't see in there for build up spots missed.

The RTV is strong as hell when applied liberally by the previous person\mechanic. I had to carefully hammer and chisel just enough without damaging the mating services then pry slowly to initiate the drain. if you look at the diff cover the spot i pried was about 4 o clock.

Have way more brake kleen (I went through 1.5 cans) and shop towels than you think you need. 2 cans would have been enough depending on the gunk build up so you may as well have it handy because the only way to clean the back of the diff without removing it is to use this liberally and of course have your catch can ready underneath.

Make sure you don't miss the pool of fluid in the back.

Having a dremel or angle grinder with a fine wire brush is NOT OPTIONAL. Saves you from having to exacto and manually fine sand the old rtv off. 2 hours vs less than 15 minutes. Inspect the spot that you chiseled. I left a little mark but nothing that would cause an issue after RTVing

Follow instructions on the RTV tube. I wait over night instead of 24 hours. 12 hours at least for me because I don't want to go through the entire thing a second time.

I read 25 foot lbs and 30 foot lbs... I went with 30

2 spots I took way too long was the removing the RTV by hand and trying to get the cover off. Try the chisel first and have a grinder available and you'll breeze through it.

 

Best silicone sealer on the market is "The Right Stuff" no need to wait to add fluid. I started working on vehicles professionally in 2003. It's then only sealer I'll ever use on a diff. Never used a gasket, never waited to add fluid, and I've never had a leak. I agree, the scotch brite pads on an angle grinder or drill are the best way to go.