GMC CHEVROLET Silverado 6500HD 2019 Owner's Manual page 404

Component Component Vendor/Lubrication Type
U-Joint Lubricant Lithium Complex Based Moly grease or
equivalent GC/LB NLGI #2
Multi-purpose Lithium Complex grease
Allison- Refer to the Allison Automatic Transmission Manual.
Conventional
Automatic
Transmission Fluid
(ATF) Fill/Change
Viscosity
Drive Shaft
Transmission
Service and Maintenance
Applicable Temperatures
403