Originally Posted By: JRed
Pretty sure Ford specs a special 75w140 in the rear diffs of certain F150s and other vehicles for some reason.
+1.
I use Supertech 75w-140 in the rear diff in my F150. 3 quarts runs around $30, but you don't change diff fluid THAT often. The stuff stinks to high [censored], btw.
If you have limited slip, find out if you need to add friction modifier along with the diff fluid.