2009 GMC Sierra 1500 Crew Cab Owner's Manual - Page 440

4. Check both sides of the dipstick and read the lower level. Repeat the check procedure to verify the reading. Consistency of Readings Always check the fluid level at least twice using the procedure described previously. Consistency (repeatable readings) is important to maintaining proper fluid level. If readings are still inconsistent, contact your dealer/retailer. Cooling System If your vehicle has the DURAMAX® Diesel engine, see the DURAMAX® Diesel manual for more information. The Cooling System allows the engine to maintain the correct working temperature. 5. Safe operating level is within the HOT cross hatch band on the dipstick. If the fluid level is not within the HOT band, and the transmission temperature is between 160°F and 200°F (71°C and 93°C), add or drain fluid as necessary to bring the level into the HOT band. If the fluid level is low, add only enough fluid to bring the level into the HOT band. It does not take much fluid, generally less than one pint (0.5L). Do not overfill. 6. If the fluid level is in the acceptable range, push the dipstick back in all the way, then flip the handle down to lock the dipstick in place. 5-30