Hello All,

I hope that someone from a Dealer or with access to Ford Factory information can answer this question.

I have a 1997 F150 4x4 with 8.8 in Diffs. For my front diff the manual calls for 75W90 and for the rear 75W140.

But I've noticed that in the manual for the 2004 that it calls for 75W90 in both diffs.

I know that running a lighter lube will help Fuel Economy, but I don't want to cause damage.

So my question is this ...

Was there a physical change in the 8.8 Differentials that resulted in the use of 90 weight as apposed to 140 weight?

Or was the change in lubes simply do to the improved quality of lubicants and the desire to increase fuel economy?

Doug

 

That has been changed. Ford later changed it to 75w140, which is what is in the rear diff of mine now.

 

The Dana EX-80 diff takes standard 75W90 or 80W90 GL-5, the others require 75W140 synthetic.

 

Hi

I have a 97 F150 also. When I went to the Dealer and checked on this for my truck, I found out that the part number for the 75W90 was superseded to the 75W140 part number. So its all the same gear lube for the differentials now.

Vince

 

You can't go *wrong* with 75W140 synthetic.