2005 Chevrolet Astro Owner's Manual - Page 202

Tow/Haul Mode Tow/haul is designed to assist while your vehicle is pulling a large or heavy load or trailer. Tow/haul is most useful while pulling such a load in rolling terrain, in stop-and-go traffic, or when you need improved low-speed control, such as when parking. The purpose of the tow/haul mode is to: Tow/haul is most effective when the vehicle and trailer combined weight is at least 75 percent of the vehicle's Gross Combined Weight Rating (GCWR). See "Weight of the Trailer" later in this section. Driving with tow/haul activated without a heavy load will cause reduced fuel economy and unpleasant engine and transmission driving characteristics, but will not cause damage. • Reduce the frequency and improve the predictability of transmission shifts, Weight of the Trailer How heavy can a trailer safely be? It depends on how you plan to use your rig. For example, speed, altitude, road grades, outside temperature and how much your vehicle is used to pull a trailer are all important. And, it can also depend on any special equipment that you have on your vehicle. The following chart shows how much your trailer can weigh, based upon your vehicle model and options. • provide the same solid shift feel when pulling a heavy load as when the vehicle is unloaded, and • improve control of vehicle speed while requiring less throttle pedal activity. Press the button on the end of the shift lever to turn tow/haul mode on and off. While activated, the indicator light on the instrument panel will be on. Tow/haul mode will turn off automatically when the ignition is turned off. See Tow/Haul Mode Light on page 3-35. 4-36