Recently had rear-end fluid replaced with 75-90 synthetic axle lube (GM P/N 12378261). Per TSB #01-00-90-001A-(02/08/2001) I should be using 75-140 P/N 12346140. This lube change was for preventive purposes only. I tow over 12,00 pounds and we travel alot. My selection of 75-90 lube was based on the owners manual and also had the Chevy dealership check to make sure this was the correct fluid. They did the drain and refill. Edited by: XFlatTopper

you will be fine with the 75-90. Dont look like your towing heavy enough to worry about the 140


Eric

Are there any drawbacks to the 75-140 in the Northern climate, as opposed to using the stock 75-90?


I realize both are a 75 weight oil, and the only difference is the flow charactoristics at 200 Deg F.

http://www.dieselplace.com/forum/smileys/Ermm.gif Isn't the 75-140 for the 3500HD? Thought our 3500s still used the 75-90.