2003 GMC Sierra 1500 Pickup Owner's Manual - Page 401

Get the vehicle warmed up by driving about 15 miles (24 km) when outside temperatures are above 50°F (IOOC). If it's colder than 50°F (IO"C), drive the vehicle in THIRD (3) until the engine temperature gage moves and then remains steady for 10 minutes. A cold fluid check can be made after the vehicle has been sitting for eight hours or more with the engine off, but this is used only as a reference. Let the engine run at idle for five minutes if outside temperatures are 50°F (IOOC) or more. I f it's colder than 50°F (lo%), you may have to idle the engine longer. Should the fluid level be low during this cold check, you must check the fluid hot before adding fluid. Checking the fluid hot will give you a more accurate reading of the fluid level. Then, without shutting off the engine, follow these steps: 1- The red transmission dipstick handle with the graphic is located at the rear of the engine compartment, on the passenger's side. See Engine Compartment Overview on page 5-12 for more information on location. Checking the Fluid Level Prepare your vehicle as follows: 0 1. Flip the handle up and then pull out the dipstick and wipe it with a clean rag or paper towel. 2. Push it back in all the way, wait three seconds and then pull it back out again. Park your vehicle on a level place. Keep the engine running. With the parking brake applied, place the shift lever in PARK (P). With your foot on the brake pedal, move the shift lever through each gear range, pausing for about three seconds in each range. Then, position the shift lever in PARK (P). Let the engine run at idle for three minutes or more. 0 0 0 5-26