Recommended Fluid
WARNING: This page does not describe the selected car, but rather 26 other vehicles, including the 1983 GMC Vandura Special, 1983 GMC Vandura, 1983 GMC Value Van, 1983 GMC Suburban, and 1983 GMC S15 Pickup. However, it is still accessible from the selected car via links, so may be relevant.
All "S" series trucks, 4-speed manual transmission and the New Process 833 4-Speed Overdrive transmission use Dexron II automatic transmission fluid.
Isuzu 69.5 MM 5-speed transmission and all 5-speed transaxles use 5W-30 engine oil rated SF or equivalent.
All other transmissions use 80W or 80W-90 GL-5 multipurpose gear lubricant or equivalent.