Edmunds Answers



  • MrShift@Edmunds 08/23/12 4:28 pm PST

    Okay...the T/H switch is a computer switch that lengthens the shift points, so that you will rev higher in each gear before shifting. It doesn't keep you out of overdrive per se.

    Most owners seem to think that it makes most sense to use the T/H when your tow load is perhaps 1/2 to 3/4 the tow capacity of the truck---so you don't have to use T/H every time you hitch up a small trailer.

    I'd say that T/H would always be a good idea if you are hauling up in the mountains, and I'd even suggest that you shift manually down to 3rd gear, even if you were in T/H, just to keep the heat down in the transmission. But I wouldn't manually downshift to 3 unless you felt the truck constantly trying to downshift/upshift (called "hunting").

  • morin2 08/23/12 9:04 pm PST

    I had the same truck, same year, Z-71, 5.3 liter 4x4 with the tow/haul button and it functions exactly as Mr. Shiftright said. It does much more than the older O/D off switches - that merely turned the OD off - because your tow/haul button extends the shift points so the truck has more power while towing. The increased rpms per shift point will be very noticeable to you. When in doubt, use it - you can't hurt anything (except for fuel economy) by using this switch. I would also use it for ascending steep hills - even without a load. Its a great feature.

    One thing that is easy to forget is that when you turn off your engine, the tow/haul mode also turns off. So if you stop for gas, remember to turn on the button again. You'll get a tow/haul mode indicator light on your dash.


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