2007 GMC Sierra 1500 Pickup Owner's Manual - Page 500

Manual Transmission Fluid When to Check Manual Transmission Fluid A good time to have your manual transmission fluid checked is when the engine oil is changed. See Additional Required Services (Gasoline Engine) on page 621 to find out when to change your transmission fluid. 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: How to Check Manual Transmission Fluid Because this operation can be a little difficult, you may choose to have this done at the dealership service department. If you do it yourself, be sure to follow all the instructions here, or you could get a false reading. Notice: Too much or too little fluid can damage your transmission. Too much can mean that some of the fluid could come out and fall on hot engine parts or exhaust system parts, starting a fire. Too little fluid could cause the transmission to overheat. Be sure to get an accurate reading if you check your transmission fluid. 500 5-speed for VORTEC™ 4300 V6 and 4800 V8 engines shown, other manual transmissions similar 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.