2010 GMC Savana 2500 Cargo Owner's Manual - Page 286

If it is decided to check the fluid level, be sure to follow all the instructions here, or a false reading on the dipstick may occur. 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. Wait at least 30 minutes with the engine Off, before checking the transmission fluid level if the vehicle has been driven: the engine run at idle for five minutes if outside temperatures is between 15°C to 32°C (60°F to 90°F). Should the fluid level be low during this cold check, the fluid must be checked Warm or Hot before adding fluid. If the outside temperature is colder than 15°C (60°F) or hotter than 32°C (90°F), a cold check cannot be performed. A warm fluid level check can be performed by driving the vehicle under lightly loaded conditions and outside temperatures between 10°C to 27°C (50°F to 80°F). The vehicle should be driven for at least 15 miles before performing a warm check. Checking the fluid Warm or Hot will give a more accurate reading of the fluid level than a cold check. Because the vehicle is equipped with a high-efficiency air-to-oil cooler, the transmission fluid temperature may not reach the required Hot fluid level checking temperature under normal lightly loaded driving vehicle conditions. • In hot weather, when outside temperatures are above 32°C (90°F). The vehicle is heavily loaded. At high speed for quite a while in hot weather. In heavy traffic and hot weather. While pulling a trailer. Checking the Fluid Level Prepare the vehicle as follows: 1. Park the vehicle on a level place. Keep the engine running. 2. With the parking brake applied, place the shift lever in P (Park). After driving under these conditions, a hot check can be performed. The fluid should be Hot, which is 71°C to 93°C (160°F to 200°F). A cold fluid level check can be performed after the vehicle has been sitting for eight hours or more with the engine Off, but this is used only as a reference. Let 6-24