Q. Tow/Haul vs. Normal Mode - If I use use Tow/Haul without a trailer, is that a problem? And vice versa?
A. T/H can be used at any time, even when not towing. Some drivers may not like the T/H shift characteristics when the vehicle is lightly loaded, and thus normal mode would be selected. When not heavily loaded, some drivers switch from Normal to T/H mode during closed throttle downshifts from highway speeds to help slow the vehicle and then switch back to Normal mode after they've stopped. If the driver chooses not to use T/H when towing or heavily loaded, he/she can expect to see higher transmission sump temperatures, more wear and tear on the brake system, and increased shift cycling. Back To Top
Q. Tow/Haul vs. Normal Mode - What's the difference between Tow Haul and Normal Mode?
A. Tow/Haul (T/H) shift mode significantly changes the transmission's shift pattern to reduce shift cycling and to deliver better performance, control, and cooling when towing/hauling heavy loads. For instance:
* Upshift points are raised at light to mid throttle position to use more of the engine's available power for accelerating.
* Downshift points are raised to enhance engine braking to help slow the vehicle.During deceleration, the torque converter clutch (TCC) remains applied at closed throttle to much lower vehicle speeds to significantly improve the effect of engine braking.
* During acceleration, the TCC is applied in 2nd range and remains applied in 3rd, 4th, and 5th. This improves the drivetrain efficiency and significantly lowers transmission sump temperature when towing heavy loads. In Normal mode, TCC generally applies only in higher ranges and is dependent on throttle position
A forum community dedicated to Chevrolet and GMC diesel truck owners and enthusiasts. Come join the discussion about duramax engines, performance, builds, modifications, classifieds, troubleshooting, maintenance, and more!