GMC CHEVROLET Silverado 6500HD 2019 Owner's Manual page 405

404 Service and Maintenance
Component Component Vendor/Lubrication Type
Rear Drive Axle(s) Mineral Oil
MIL-PRF-2105E, API MT-1, GL-5
2837 Synthetic Lubricant.
Do not mix conventional (mineral bases)
lube with synthetic oil.
Rear Axle
Gear oil meeting
Viscosity Applicable Temperatures
75W 40 °C to 26 °C ( 40 °F to
75W-80 40 °C to 27 °C ( 40 °F to
75W-90 40 °C to 38 °C ( 40 °F to
75W-140 40 °C and above ( 40 °F
80W-90 26 °C to 38 °C ( 15 °F to
80W-140 26 °C and above ( 15 °F
85W-140 12 °C and above (10 °F and
75W-90 All Temperatures
15 °F)
80 °F)
100 °F)
and above)
100 °F)
and above)
above)