2001 GMC Sierra 1500 Pickup Owner's Manual - Page 370

How to Add Fluid Refer to the Maintenance Schedule to determine what kind of transmission fluid to use. See "Recommended Fluids and Lubricants" in the Index. Add fluid only after checking the transmission fluid while it is hot. (A cold check is used only as a reference.) If the fluid level is low, add only enough of the proper fluid to bring the level up to the HOT area for a hot check. It doesn't take much fluid, generally less than one pint (0.5 L). Don't overfill. Manual Transmission Fluid When to Check A good time to have it checked is when the engine oil is changed. See your maintenance schedule to find out when to change your transmission fluid. How to Check Because this operation can be a little difficult, you may choose to have this done at your GM dealership service department. If you do it yourself, be sure to follow all the instructions here, or you could get a false reading. NOTICE: We recommend you use only fluid labeled DEXRONR-III, because fluid with that label is made especially for your automatic transmission. Damage caused by fluid other than DEXRONR-III is not covered by your new vehicle warranty. 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. Be sure to get an accurate reading if you check your transmission fluid. D After adding fluid, recheck the fluid level as described under "How to Check." D When the correct fluid level is obtained, push the dipstick back in all the way. 6-28