Amsoil in differential

[Jaddison]

For my '89 with 130k miles... use 90 or 140 wt synthetic in differential (front and rear).

 

[paccool]

I use a multi weight. It's not Amsoil but another good quality synthetic. Is 85/140 weight. I think that is what you were refering to when you asked if 90 or 140. The multi weights will take care of the temperature swings. I'm sure some of the Amsoil boys will jump in here and explain this better than I have.

 

[Randy J]

Currently I'm running 75W90 in the front & rear diffs, but I'm getting ready to service them again. I'm going to go with 75W140 in the rear this time, just because. I'd recommend going with the 75W90 in the front, and in the rear unless you tow an awful lot. Although you can't go wrong with it, I think the 140 is overkill. Also, the 140 costs more.

 

[chuck3]

Amsoil

75w90 in rear, original oil in front, seems to work fine.