I think with 150,000 on the clock it's about time to overhaul the rear axle on my truck. I bought all the necessary bearings, gaskets, and seals, along with some synthetic gear oil. Just wondering if anyone has any pointers or tips or things to watch out for before I tear into this thing.

 

It's pretty straight forward. Without a pinion depth gauge I always start with the original pinion shim. That seems to work pretty good. Just set all your preloads (don't forget to lube the bearings) and run a gear pattern. As long as you have a good gear pattern and you set all the bearing preloads and gear backlash you should be good to go.

 

I've heard through the grapevine that posi's would actually respond better to a "mineral" (or "conventional" - I guess) gear oil rather than a synthetic. RP, I heard holds up to heat real well, and their 80w-90 is not a synthetic (and already has the posi additive), but you pay for the purple stuff. I put Mobile1 (and GM friction modifier) in my Yukon back-when, and had no negative side effects until I sold it 20k miles later. I still figured I'd pass on what's been mentioned at the skutlebutt in the recent oil debate.

 

Does that hold true for gear type posi's too? I wouldn't figure it would make a whole lot of difference since there are no clutches in the rear end.

 

I'll be doing mine in a few weeks too. If you have a shop press, bearing splitter, magnetic base/dial indicator and all the various hand tools it should be alright. Since you're not swaping ratios shiming should be a walk in the park.

FWIW, I've always used non synthetics and Ford's friction modifier. Never had an issue with 3 different vehicles and 3 different types of rear ends.