Depends on make, model, year. Most use a gear oil, could be 75w90, 80w90, 75w140......Toyota corolla 1991 automatic
75W-90
75w140 synthetic
You can use any SAE certified rear differential fluid in your 1970 Chevrolet. The 1970 Chevrolet differential fluid can be checked from the differential fluid check port.
VTM-4 available from Honda only
80w90...with a diff additive for the rear
75W-90 in the rear differential. 80W-90 in the front differential (4x4 models). This is according to the 2007 Chevrolet Suburban owner's manual.
It has a transaxle, there is no separate differential fluid.
75w140 synthetic with limited slip additive.
What is the fluid capacity front differential 2004
In the differential
80w-90 if ambient temperature is under 104F or 40C
I would take it to an authorized Chevy dealer to check it out.