Recommended Fluid: Transmission
WARNING: This page does not describe the selected car, but rather 19 other vehicles, including the 1991 Oldsmobile Bravada, 1991 GMC Vandura, 1991 GMC Value Van, 1991 GMC Sonoma, and 1991 GMC S15 Jimmy. However, it is still accessible from the selected car via links, so may be relevant.
The 77mm 5-speed and 4500 5-speed use Dexron-II ATF. The 117mm 4-speed uses API GL5 SAE 80W90 gear lubricant. Manufacturer recommends using Manual Transmission Fluid (1052931) in 85mm 5-speed.