Vehicle in question is an '02 Avalanche Z71, and I find the owner's manual rather vague as far as oil specifications are concerned. Lubricant capacities are not listed, so I'm still trying to figure those out. But it also does not specify whether GL-4 or GL-5 lubricant should be used in the front and rear differentials...it just lists GM spec. For the rear axle, it just says:
Originally Posted By: Owner's Manual
SAE 75W-90 Synthetic Axle Lubricant (GM Part No. 12378261) or equivalent meeting GM Specification 986115.
For the front:
Originally Posted By: Owner's Manual
SAE 80W-90 Axle Lubricant (GM Part No. 1052271 or equivalent).
The only synthetic axle lube I can find here are 75W-140, and it does not meet the above mentioned spec. Mineral based lubes, OTOH, are all 80W-90. I've found GM Vehicle Care 80W-90 meeting GL-5 spec, but 9986115 isn't listed on it either. It's the same with CRC Sta-Lube and Motorcraft Premium Rear Axle Lubricant 80W-90. Question is, can I just use 80W-90 in both diffs and change them out every 25,000 miles?
I've really got no other choice to be honest.
Originally Posted By: Owner's Manual
SAE 75W-90 Synthetic Axle Lubricant (GM Part No. 12378261) or equivalent meeting GM Specification 986115.
For the front:
Originally Posted By: Owner's Manual
SAE 80W-90 Axle Lubricant (GM Part No. 1052271 or equivalent).
The only synthetic axle lube I can find here are 75W-140, and it does not meet the above mentioned spec. Mineral based lubes, OTOH, are all 80W-90. I've found GM Vehicle Care 80W-90 meeting GL-5 spec, but 9986115 isn't listed on it either. It's the same with CRC Sta-Lube and Motorcraft Premium Rear Axle Lubricant 80W-90. Question is, can I just use 80W-90 in both diffs and change them out every 25,000 miles?
