rear axle preventative maintance

[bucannon]

i bought a used 10 bolt rear for my truck with posi, and im about to go on a road trip, so i want to make sure i dont break down because of a rear end failure.

so when i tear it open to put in new fluid what else should i look for to be sure its not near failure. thanks for any help

[68Gold/white]

Make sure there is no glitter in the old oil, look at the axles where they ride in the bearings, they can wear into the axle.

Make sue you get a bottle of posi additive from a GM dealer (there are other additives, not all work, though).

I fill the diff w/ 80-90 after puring in the additive, until it gets to the oil plug hole. I then install the plug and install a little extra oil through the vent hole. I've never had a problem doing this.

Do NOT use synthetic gear oil. Install new axle seals. If the pinion seal doesn't look like its been leaking, leave it alone.

[PurdRob]

Originally Posted by 68Gold/white

Do NOT use synthetic gear oil. Install new axle seals.

Why do recommend conventional gear oil over synthetic? Is it due to the likelihood of synthetic finding a way to leak or ?

[GASoline71]

Synthetic oil and posi-traction rear ends don't get a long all that great. I'm guessin' by sayin' it will allow the clutches to slip too much.

The new Eaton Posi I put in the 12 bolt in my truck had a big ol' tag on it from the factory "DO NOT USE SYNTHETIC GEAR OIL". It will also void the warranty in most new posi units.

Gary

[bucannon]

i thought about using Royal Purple, but you recommend using conventional with posi additive?

[68Gold/white]

I've used the GM additive w/ GM oil, and Used the GM additive w/ other brands of gear oil.

Just make sure whatever oil you use is NOT synthetic.

[bucannon]

okay so ive never done any work on a rear axle so does anyone have a write up on how to correctly take apart and "rebuild" one of these. i dont want to mess up.

[clinebarger]

Originally Posted by bucannon

okay so ive never done any work on a rear axle so does anyone have a write up on how to correctly take apart and "rebuild" one of these. i dont want to mess up.

You need certain tools & good feel for what your doing when rebuilding a differential.
Have you removed the cover & verified its a "clutch type posi" ALOT of 10 bolt have a Eaton Gov-Loc or "Gov Bomb" lockers & when they break THEY BREAK, Not a very good posi in my opinion.

[bucannon]

i know its an aftermarket posi unit and its got 4.88 gears.

i will most likley put in gears that arent soo steep so i can go on a road trip soon and i wanted to go ahead and prevent an on road breakdown. should i bring a junkyard open carrier and other parts in case it does go out on the road?

[clinebarger]

The Eaton Clutch-type posi carrier is a GREAT unit, Im talking about the Eaton Gov-loc POS. that was installed from the factory.

You cant change carriers on the side of the road without carrying alot of tools. That mentality does work for diffs that you can drop the whole "pumpkin" out like Ford 9" & Chrysler 8 3/4".

[Captainfab]

If you've never done any work on a differential before, trying to setup a new set of gears for the first time and then heading out on a trip, probably isn't the best idea. As clinebarger said, you need some specialty tools, along with much patience to setup a differential.

[bucannon]

i was afraid this might be the situation, so what can i do to make sure it doesn't fail on me or what can i do to best prevent this. replace bearings and seals im assuming. so how do i do it?