What Diff Fluid to use??!?
 

Hey there all,

The book calls for 90w diff fluid...

I went to the store and the highest one they had was 85w-140

Will that work?!?

Just put new axels in... and i picked up a new diff cover that is way better than the one i got so i don't mind swapping it out..

I use syntheic 85 w 140. but do find out if you have a LSD.

The 85W - 140 is slightly thinner than 90 when cold and thicker when hot. Unless someone offers specific reasons not to use what you have, I'd use it.

SAE 80W-90 GL-5, commonly called "90 weight". Any brand is fine as long as it has the API "donut" with that EXACT information, and it should be commonly available at any consumer oriented parts store or chain. DO NOT USE A GL-4 IN A HYPOID AXLE!

If you live in a arctic climate, use 75W-90 GL-5, which has a "synthetic" base for a wider viscosity range, but it's more expensive.

SAE 85W-140 is designed for large, heavily loaded low speed axles, such as big rigs. It's doesn't belong in any passenger car or light truck, and no manufacturer of passenger cars or light trucks, including Daimler-Benz has EVER recommended it for those applications.

If you have a clutch-type mechanical LSD (like on a 190E 2.3 16V) you also need a bottle of limited slip additive, which you can buy from Mercedes, Ford, or GM dealers, but the same thing is a lot cheaper from NAPA.

Duke