45Ricochet wrote:
coolbreeze01 wrote:
Synthetic 75w-90 in the rear is OE. Some are using 75w-140 due to high temps.
75w-90 in the front.
That's what I ran also, I believe the manual mentions the 75-140 for towing heavy.
It does on my 2001 dually. I run 75w-140 because the book recommends it. I just checked my differential (I was going to say "rear end" but reconsidered LOL) temperature yesterday after 2 hours @ 65 mph, about 80 degrees ambient temperature, OEM differential cover, and lots of steep hills (Ozarks). It was showing 174 degrees. I see nothing wrong with that temperature.
