I just wondering how many of XOC members are using straight Mobil 1 75W90 (no user mixed additives)in their front / rear diffential?

This saturday, I changed the rear differntial oil with straight M1 75W90 and seems like I maybe getting a slight vibration after changing the oil. The existing oil seemed thicker than M1. Since, I bought my X used I have no idea what was in there. I am planning on changing the front differntial with M1 75W90 next weekend and was wondering if I need to do anything to rear differntial. TIA

Brent, thanks for the great instructions.

I've got Mobil 1 in the front diff, and had it in the rear diff for a good while, no problems other than it was just too slick for the LSD to do much of anything. I switched it out with 80W90 Coastal brand that contains no LSD additive to try and get more hook-up, and it did make a little difference. I'm now running Amsoil 80W140 in the rear to try and get even more from the LSD. It spent a few weeks in the rear of a friend's 95 Pathfinder (they have much tighter LSDs) and he put 80W90 back in because the clutch pack was getting to cranky. My looser LSD has only twitched once from it.

Anyway, Mobil 1 75W90 shouldn't cause any problems, and it already contains the LSD additive anyway.

Brent

Make sure you topped of the diff correctly.
My personal experience is that Mobil1 GL5 75w90 doesn't have enough LSD additive. Buy some.