Checking Fluid Level
WARNING: This page does not describe the selected car, but rather 28 other vehicles, including the 1986 GMC Vandura Special, 1986 GMC Vandura, 1986 GMC Value Van, 1986 GMC Suburban, and 1986 GMC Safari. However, it is still accessible from the selected car via links, so may be relevant.
Check lubricant level at transmission filler plug hole. Lubricant should be level with bottom of hole. Add as needed.