tow haul mode
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Freshman User
Joined: May 2003
Posts: 44
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tow haul mode
I know that the tow haul mode locks the convertor and holds the truck from constantly shifting when under load but how is it supposed to act when going down hills etc.
I know when I first bought my '03 I would be going down hill and touch the brake slightly and the truck would shift down and holdback as I went down hill. After a reflash it didn't act that way any longer.
I now have an '06 and it does nothing when decelerating until you are almost stopped and sometimes it downshifts really hard and sounds brutal.
How are they supposed to perform?
To reprogram the tranny does it involve the engine at the same time> Afraid to reflash because engine works perfect other than a guzzler (10 mpg).
I know when I first bought my '03 I would be going down hill and touch the brake slightly and the truck would shift down and holdback as I went down hill. After a reflash it didn't act that way any longer.
I now have an '06 and it does nothing when decelerating until you are almost stopped and sometimes it downshifts really hard and sounds brutal.
How are they supposed to perform?
To reprogram the tranny does it involve the engine at the same time> Afraid to reflash because engine works perfect other than a guzzler (10 mpg).
Elder User
Joined: Dec 2006
Posts: 594
Likes: 0
From: New Jersey
The tow/haul mode on the '03's was very aggressive, especially if you got an early one and did not have it flashed. If you are comparing your '03 to the '06 this is why you are seeing a difference. I had an '03 and now an '06 as well and initially the tow/haul in the '03 would put you through the windshield at times. Mine was so aggressive and would bang in so hard that I thought someone hit the back of my trailer. My '06 is definately less aggressive but it does work and does make a difference. You have to keep in mind that the amount of decelleration that tow/haul provides directly depends on how fast or hard you are trying to stop and if you are going down a hill or on level ground you will see a difference. The system detects many things, like the position of your brake pedal and the rate of decelleration for the position you are at. Basically it is trying to figure out in nanoseconds how quickly you need to stop and the best amount of engine braking to apply to make it as smooth as possible. I have found that if the tow/haul rate is not aggressive enough for me when going down a hill that a little hard stab on the brake pedal will tell it that you need more engine brake and it will get more aggressive.
Senior User
Joined: Sep 2006
Posts: 253
Likes: 0
From: Santee, CA
I have an 06, so cannot compare to the 03. One of the things that is documented, and I have experienced it with the 06, is it will monitor the speed. If you are going downhill and it is holding speed, then applying brake is simply that. If while going downhill (with no throttle being given) and you are gaining speed, then a slight tap on the brake will cause it to downshift. I assume from that that is knows you are trying to slow, but are in fact speeding up thus will downshift to assist. That may be one of the changes.
Posting Guru
Joined: Dec 2006
Posts: 1,078
Likes: 0
From: Kansas City/Breckenridge
I agree that the 03 is extremely rough. The roughness can be extremely annoying though especially when you tap the brake and the tranny automatically puts you at 3500 revs throwing you through the windshield and it wont ****ing upshift so you can start moving forward again.
I would be happy with what you have. Just turn your trailer brakes up a little.
I would be happy with what you have. Just turn your trailer brakes up a little.
