I found an online OM that said my Jeep could use a 90 weight gear oil in both axles, but after a bit more clarification on a few Jeep forums (and proof with a factory service manual), the front Dana 30 does indeed need a 75w-140 gear oil regardless of having LSD or not. Regardless of what is required, many folks online still run a 90 weight conventional gear lube in severe conditions.. issue free.
A rear non-LSD D35 can use a 90 weight oil, but a 140 weight is preferred for severe use, which seems backwards to me. A member suggested I use a 140 weight oil because of my slightly oversized tires (31's) which I guess is a good idea. Thoughts?
Anyways, a 140 weight in the front and a 90 weight in the rear for open diffs and normal use just seems backwards even though it still would have been slightly less resistance. I have no preference one way or the other, but I'll admit I was looking forward to A.) Cheaper gear oil. And B.) Possibly getting that 1/10th of a mile better fuel economy (or whatever it would have been.)
A rear non-LSD D35 can use a 90 weight oil, but a 140 weight is preferred for severe use, which seems backwards to me. A member suggested I use a 140 weight oil because of my slightly oversized tires (31's) which I guess is a good idea. Thoughts?
Anyways, a 140 weight in the front and a 90 weight in the rear for open diffs and normal use just seems backwards even though it still would have been slightly less resistance. I have no preference one way or the other, but I'll admit I was looking forward to A.) Cheaper gear oil. And B.) Possibly getting that 1/10th of a mile better fuel economy (or whatever it would have been.)