Tow/Haul and Shifting into Manual Mode

Discussion in 'GM Powertrain' started by Ganderson, Jun 6, 2010.

  1. Ganderson

    Ganderson New Member

    I have a 2010 Silverado 4x4 with a 5.3 and 3.42 rear end. I'm wondering if its okay to shift the transmission into Manual mode while towing in Tow/Haul mode?

    The truck is less than two weeks old and I didn't see this question answered directly in the owners manual.

    Thanks, in advance, for your replies,
  2. wis bang

    wis bang Rockstar 100 Posts

    The way I understand the tow mode is it changes the shift points and limits OD so you don't need to do it manually...
  3. at4rxj

    at4rxj New Member

    I've done it. As far as I know it's fine... lol.

    I towed through the hill country recently and my transmission was shifting back and forth at some points. I slowed down a little and manually kept it in the lower of the two gears, and it worked great.
  4. Ganderson

    Ganderson New Member


    Thanks for the first hand feedback. I was thinking it was okay to do but I didn't want to break the truck before it turned 3 weeks old. : )

    What sort of towing mileage do you get? Is yours a 1/2 ton also?

    Again, thanks,
  5. 1flyfisher

    1flyfisher Rockstar 4 Years 100 Posts

    What do you mean by the lower of the two gears?
    Is there only two gears used in tow haul mode or did you just shift down a gear between the two gears the tranny was using?

    I have a new 2010 GMC Savana 5.3 with 3.42 and tow haul. But I don't know exactly how or when to use tow haul and how it works.
    What does tow/haul do?

  6. Ganderson

    Ganderson New Member


    Basically Tow/Haul mode resets the shift points in the transmission to provide more torque when pulling a trailer or hauling a heavy load. There are times, like in hilly country, that the transmission will automatically go in and out of overdrive. (these would be 5th and 6th gear in the new 6 speed transmissions and 3rd and 4th for those with a 3-speed with overdrive tranny.)

    What "at4rxj" did was to shift the transmission into "manual" (while the tow/haul mode was still selected) and make the choice of staying in the lower gear through the hills and eliminate the "searching for the right gear" the transmission had been doing.

    It sounds complicated but if you've ever taking your Savana out of overdrive to give you more power in hilly country then you've done exactly what at4rxj did.

    These new vehicles have so many electronics on them it seems to take a village to drive 'em. : )

    How do you like your Savana? My wife and I have been van owners since 1978 when we owned a 1972 VW Bus that I converted into a camping van. We've had a couple of Fords since then with the last one being a 1999 Extended E250. That one is in the driveway with over 170000 miles on it. Lots of memories.

  7. at4rxj

    at4rxj New Member

    I mean it was going back and forth between two gears (I think 3rd and 4th but not sure) so I put it in manual and kept it in 3rd. Sorry for not being clear.

    I didn't calculate my total mileage, but on the highway I was getting between 12-16 depending on how fast I went and how hilly. I'm sure that overall it was probably somewhere around 9 or 10 average. It's a half ton 4x4 with the 5.3 and I was pulling a boat and trailer around 5500-6000lbs total.

    One thing that surprised me was that the active fuel management thing still shut off 4 of the cylinders in tow/haul mode. I noticed it on the freeway when coasting.

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