So I went to the GM Dealer today, and in the parts department they told me "You need about 2 Lt. of Autotrack II Fluid for the Front Differential. So I finished servicing it, and put it back together. This seems weird, I put it in, and it drives fine. I know the T-Case uses it, but I just want to be sure that i'm not making a big mistake.

 

we use 80w 90 at the dealer i work at. not sure what the weight of the autotrack is though

 

Yea, It seems really weird to me. I mean it drives fine, probably better than it did with the old oil and mud in it from after I sank it (part of the reason I serviced it) Its not hard to change, I may change it if need be. I plan on servicing the rear axle and that takes 75w90, I believe.

 

That's odd they said to use that for the front diff. I know I put 80w-90 for my front diff and rear diff. I still need to drain out my transfer case and add new fluid but I've been too busy to do that.

 

There shouldnt be mud in it. the only way mud and water can get in is through the ven tube which i believe goes up to the left of the radiator. If you go through really deep stuff i would recomend extending the tube.

Also 80w90 goes in the front and the rear

 

Never heard of it being used in a differential... 75w90 synthetic gear lube is what I used in the front and rear diffs on my old 2000 Bravada. There is nothing up front which would need the AutoTrak II fluid...

My FSM's and online tools all call for either GL-5 80w90 or Synthetic 75w90 gear lube for front and rear axles.

 

Old post but thought I'd chime in. I accidentally put AutoTrac II in my front differential and it ran great. When I discovered my mistake, I converted back to GM gear oil. Didn't run as well but I need the Bravada to last so I am running factory specs. Ran it about 500 miles with the wrong fluid (1999 Bravada)