Whats the best gear oil to use in 3rd gen AAM rear ends? Mopar stuff is super expensive. Considering redline, but I'm unsure of which one to use.

 

If you are towing close to the max GCWR of your truck then choose Redline 75W140. If you are towing light use 75W90.

Casey

 

Alot of guys, including myself, are using Mobil 1 75-90.
It is easy to get at the local Autozone or Advance Auto.
About $8 per quart. You will need to buy 8 quarts to fill
both front and rear (with a little left over).

Carl

 

Make sure you choose whatever you decide to use having the GL-5 specs. I used the Castrol Syntec 75w-90 full synthetic. I was planning on the Mobil 1 synthetic 75w-90, but could not find it at the time available for me. I don't tow that often so as recommeded above the 75w-140 may be the best for heavy towing.

Tony