I'll be chaning my rear end tonite, and was wondering if I should go with Mobil 1 gear lube, or just normal Mobil. Due to time and money restraints, I can't order any Redline or other similar products. Just normal dead dinosaur, or Man made synthetic. I'll be using a 3.73 gear if that makes a difference.

One person (derty) suggested that I just use Reg. Mobil....I just wanted some other views on this.

Milo.

 

Go with mobil 1 synthetic. But pick some GM rear end additive for good measure, can't hurt.

 

I use mobil one synthetic, bbut since the change I have noticed a distinct gear whine at ~50 mph when I am off the throttle. I think the synthetics dont have the quieting abilit of the regular dino oils...
I change it every 9m or so and it always comes out nice and clean, inspite of the autocrossing/drag racing abuse.

 

I use red line oil in my car.I have over 50 launches on it and my rear hasnt blown. Plenty of 1.7x short times.I dont know if that means anything but its all I have ever used

 

GM specifies synthetic gear lube in all it's LS1 rear ends. I use Royal Purple synthertic gear lube, it doesn't need the limited slip additive because it's already in the gear lube. I have over 25K on my car now without any gear noise or whine. Do NOT use regular gear lube, use synthetic gear lube only! Make sure the gear lube has limited slip additive already in it or buy GM limited slip additive ($9.00/can - 2 cans required).

 

Um. . . What's with this additive when talking about the newer F body cars? When I bought my '99 Z28 in July of this year I researched this VERY thoroughly, talked with several GM parts depts., bought a set of Helms service manuals for this car, etc. After all of this, it became clear to me that since GM changed over to the Torsen rear end on posi equipped cars, and dropped the old Auburn posi diffs with clutches in them requiring "additive", these newer posi rearends have no need for anything but a good quality synthetic 75/90 weight of your choice.

GM tried to sell me their brand of the stuff for $32.00 per quart! (sucker born every day) I ain't one of 'em.

Get the synthetic of your choice, but don't let anyone tell you that a Torsen posi requires any additive like the Auburn diffs with clutches did for many years. My info is that the change took place with the 1999 model year, and the 1998 & older cars still had the Auburn type that required the posi additive.

Good luck. . .