2009 GMC Savana Van Owner's Manual - Page 231

• Then, during the first 500 miles (800 km) that a trailer is towed, do not drive over 50 mph (80 km/h) and do not make starts at full throttle. This helps the engine and other parts of the vehicle wear in at the heavier loads. Weight of the Trailer How heavy can a trailer safely be? It depends on how the rig is used. For example, speed, altitude, road grades, outside temperature and how much the vehicle is used to pull a trailer are all important. It can depend on any special equipment on the vehicle, and the amount of tongue weight the vehicle can carry. See "Weight of the Trailer Tongue" later in this section for more information. Maximum trailer weight is calculated assuming only the driver is in the tow vehicle and it has all the required trailering equipment. The weight of additional optional equipment, passengers and cargo in the tow vehicle must be subtracted from the maximum trailer weight. • Vehicles with an automatic transmissions can tow in D (Drive). Shift the transmission to a lower gear if the transmission shifts too often under heavy loads and/or hilly conditions. Three important considerations have to do with weight: • The weight of the trailer • The weight of the trailer tongue • The weight on the vehicle's tires Also see Tow/Haul later in this section for information about the Tow/Haul button and the Tow/Haul indicator light. 4-29