On my Savana 3500 with a locking differential, GM recommend using gear oil # 1052271 without friction modifier.
This is the same oil they recommend for the open diff. version, and they say to use a 80W90 or equivalent for this diff.. No word as what is the #1052271.
I am using a synthetic 75W90 oil without a friction modifier, but sometimes, the axle is showing a behavior like it needs the additive. I would like to know if I have to use the friction modifier or not. Is it included in the GM oil already, making it unnecesary to put additionnal additives? Is the GM oil a 80W90 mineral?
I know too that GM has a service bulletin on Rear axle lubricant - recommendations(#01-00-90-001A), but I don't have access to it.
Thanks for helping.
Richard.Edited by: Richard7
This is the same oil they recommend for the open diff. version, and they say to use a 80W90 or equivalent for this diff.. No word as what is the #1052271.
I am using a synthetic 75W90 oil without a friction modifier, but sometimes, the axle is showing a behavior like it needs the additive. I would like to know if I have to use the friction modifier or not. Is it included in the GM oil already, making it unnecesary to put additionnal additives? Is the GM oil a 80W90 mineral?
I know too that GM has a service bulletin on Rear axle lubricant - recommendations(#01-00-90-001A), but I don't have access to it.

Thanks for helping.
Richard.Edited by: Richard7