Such a question is always likely to spark brand loyalty wars here , but I'll brave it! At my 4,000 interval, I changed to the synthetic Amsoil fluid. I have had good luck with it in my Ford 8.8, and decided to try the Wing. Some 10,000 miles later all is still well. It didn't increase gas mileage anything noticable, didn't make all days sunny, and didn't help me win the lottery - but it seems to be lubing my final drive just fine. Which is all I expected! I believe that any brand will do the job when changed regularly and do think that most syns are better than dino. Mobil 1, Castrol, and others make good syn lube. My choice was based on past experience, availability, and cost.
I use the Mobile 1 Red cap in the engine and the Mobile 1 75-90 syn in the rear end.
Why would you need to change the rear end oil as often as every oil change?
Seems like I never changed rear dif oil in any car I have owned. Same question goes for the brake/clutch fluid??? :?
I am using Mobil 1 redcap 15W50 in the engine and Mobil 1 75W90 in the rear end. When I went to Mobil 1 at 3500 miles, I really noticed a difference in shifting and the motor seemed to run smoother. So I went to mobil 1 synthetic in the rear at 4000.
A friend of mine chaned the oil in his bike and his cars to Amsoil at the same time. With in 6 months all three had MAJOR ENGINE FAILURES!!!!!!
He took his year old car back thje the dealer and was told that it was the oils fault, even though he never had told him up to this point that he had used that Amsoil.
He went back to his Amsoil dealer with the lab tests from his Honda (auto) test results and the Amsoil dealer just ran for the hill and will not respomd to mail or phone. He has served Amsoil, but there in another state and that could drag on.....
What I'm trying to tell to...... AMSOIL KILLS........ :evil: