Tow Haul Mode

So, when should you run in tow haul mode.

I pull a 20' boat behind my 2500HD and it really has no problems what soever pulling it at any speed. The only thing I noticed in Tow Haul mode is that it runs at slightly higher RPMs.

I think the boat and trailer runs aroun 3000 lbs. Should I run in tow haul mode with it or just when running my heavier (over 5000lbs) office trailer?

-- Bob La Londe Yuma, Az

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Reply to
Bob La Londe
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I pull a 7k lb. travel trailer with my 02 2500HD. I never use the tow haul mode. The manual says that you should use it when your truck is shifting back and forth to much. MR

Reply to
MR

I've got a '93 2500 HD. What is this tow/haul mode? I was under the impression that you should tow with the trans. in Drive, not overdrive. Is that what you're referencing here?

Garrett Fulton

Reply to
gfulton

The tow/haul mode does a couple of neat things......

....it delays your shift points so your engine stays in the sweet spot of your power curve longer, thus helping acceleration.

....it increases pump pressure, so your shifts are "crisper", thus lowering transmission heat and saving some wear-and-tear on the transmission clutches, etc.

I have a 2003 2500HD Duramax/Allison. When towing a 5th wheel camper (about

8000#) I can easily pull it without tow-haul engaged, but I notice at lease 20-degree lower tranny temp in tow-haul, especially when working in grades (either up or down).

-- ô¿ô 73, de Hans, K0HB

-- Help support youth involved in Amateur Radio.

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Reply to
KØHB

As I remember my training correctly, tow haul is designed to be used when you are towing 75% or more of your max. towing weight; which would vary depending on what truck you have.

K0BH is exactly correct is what it does. It also allows you to tow in overdrive. That Allision is a different animal all of its own!!!

Jerry H.--retired GMC sales manager

Reply to
Jerry Hamilton

I recently traded an '02 2500HD w/ the 6.0L for an '02 2500HD w/ the 8.1L and Allison and 4.10. The power increase is incredible, BUT the MPGs for the type of normal driving I do SUCK! Six miles of my one way drive is on the highway and another four is on secondary roads around 35 MPH. It just got

8.2 MPG over 26 gallons and that was driving while keeping my foot out of the accelerator MOST of the time! I know it will pull our 32' 5'er much better than the 6.0L, but good grief!!! The Allison is a very cool tranny the way it operates.

I used the tow/haul mode on the 6.0L in OD, but don't expect I will need it much with the 8.1L. My Dad hardly ever uses it on his '02 with the same engine and rear while towing their 32' TT. The 6.0L HAD to stay in 3 if the AC was on while towing. It wouldn't even think about locking up until 65 MPH w/ the AC on and then it couldn't stay there for long. Haven't pulled it yet w/ this truck as I need to get the bed sprayed and then the hitch installed. It'll wait til Spring I guess.....

Reply to
Kevin

"Tow/Haul" mode is a part of the "smart" transmission management system which first showed up in 1999 Silverado/Sierras. It electronically changes some transmission operating parameters for better performance when hauling/towing heavy loads.

Hans

Reply to
KØHB

Another interesting thing that I've noted with the Allison is that it down shifts for you when in Tow/Haul. If you're going down a grade it will down shift to help keep you off of the brakes, and when you slow to a stop, the downshifting of the tranny itself if MUCH more noticable.

Brian

02 2500HD w/ Duramax & Allison

Reply to
SpaseKase

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