2001 GMC Sierra 1500 Pickup Owner's Manual - Page 371

Check the fluid level only when your engine is off, the vehicle is parked on a level place and the transmission is cool enough for you to rest your fingers on the transmission case. Then, follow these steps: 1. Remove the filler plug. 2. Check that the lubricant level is up to the bottom of the filler plug hole. 3. If the fluid level is good, install the plug and be sure it is fully seated. If the fluid level is low, add more fluid as described in the next steps. How to Add Fluid Here's how to add fluid. Refer to the Maintenance Schedule to determine what kind of fluid to use. See "Recommended Fluids and Lubricants" in the Index. 1. Remove the filler plug. 2. Add fluid at the filler plug hole. Add only enough fluid to bring the fluid level up to the bottom of the filler plug hole. 3. Install the filler plug. Be sure the plug is fully seated. 5-Speed for VORTEC 4300 V6 and 4800 V8 engines shown, other manual transmissions similar 6-29