i own a 2002 F-150 4x4 with the 9.75 rear end . I had a question concerning the use of non-synthetic lube in this truck. Could I use dino lube(75-140 weight) and if I do do I need to use that non slip additive? any help would be greatly appreciated!!!!!!!!!!!

 

Ford uses and recommends synthetic 75w140 for your rear end. If the dino meets Ford spec then go for it, a rear end is an expensive part to replace and the 3 quarts of synthetic gear oil is cheap insurance. Most aftermarket syn lubes usually have the additive already in the bottle..Walmart and most other part stores carries the additive just in case though.

 

Does non synthetic 75w-140 even exist? You only need the additive if you have a Limited slip diff.

 

Wal Mart has the synthetic if you want to save a few bucks. dont use straight dyno, not worth the risk. Auto Zone sells a 7 oz tube of the friction modifier if you have LS rear end.