Newbie here. Just bought my first new used truck and new used travel trailer. 2002 GMC Sierra crew cab, 4x4, 2500HD, duramax/allison. Trailer is a 2002 Nash 25S; about 25' 6" (not incl. hitch); GVWR = 7,400#. Equalizer hitch. Prodigy brake controller. Haven't weighed any of it yet but I plan to. I towed the TT home yesterday, from Akron to Pittsburgh, with no issues at all! What a truck! I know what the tow haul mode is in principle. I could easily tell what it was doing as I towed the trailer home, up and down hills, through small towns, and on the interstate. It seemed to keep me in one gear LESS than the highest once I reached cruising speed of 55 mph or so, unless I flicked it off for a second (which let it shift into what I assume was 5th gear and drop the rpms to under 2,000) and then back on again. If I didn't do that, it seemed to stay in what I assume was 4th gear, and the rpms at around 55 mph stayed around 2,200 or so. My question is this: Which is the best way to use tow haul? Should I just let it do its thing? I.e., turn it on and forget about it anytime I'm towing the trailer? Or should I try to get cute and probably outsmart myself!?
I don't know the answer as I have yet to tow with my 2500hd. I would like to hear from thoes that have.... DO you take it in and out of "tow mode" as needed?? Seams to me, if I were on a flat hwy the 'tow mode' would be off, as soon as I hit the hills...Tow Mode ON... Yes? NO?
I basically enguage it and leave it. The enhanced grade braking and all is nice, as is the extra/different TC lock points and change in sift points (higher rpm and firmer). I've really not noticed any behavior I didn't want when towing.
My experience towing my 5th indicates that in T/H, it won't shift to OD until you hit 57 mph. The aforementioned method of clicking it off then back on will work though. That weight is nothing for your truck. Marc
I just turn the T/H on and let it do the thinking. It's a lot smarter than I am and I like the downshift braking.
Tow Haul I own a 2003 GMC 2500 hd duramax crew cab short bed 4x4 and tow a 37 foot Everest 343L. I pull this trailer over the coast range mountains to the coast twice a year and love how the tow haul works. I leave my transmission in tow haul the minute I hook up to the trailer and just stick my foot into it and listen to it purr. I have installed banks exhaust, edge with attitude and a new air cleaner system.
I just towed my fifth wheel, approx 16k when fully loaded, for the first long trip with my dually. Went from the high desert of Ca to Ramona Ca, lots of hills, biggest grade was 7%. I enjoyed the use of the tow haul mode. I set the Edge in tow mode and had to turn off the OD a few times. The TH mode added a lot of control, but I did notice that taping the breaks made the trans down shift more often. At one point I was in the 3000 rpm range and had trouble getting out of the TH mode to lower my r's; I turned it off and back on again and let it do it's thing. I tend to use TH in traffic and stopping situations, since my breaks feel a little soft, much better than my 98 chevy dually with a 454.
There really is no right or wrong, across the board answer. The best way to use it is to go with what makes for the best drivability for your specific needs. I wouldn't worry about being outsmarted or hurting anything, it's only there to make your life easier. If it's doing something specifically that's making your life tougher, and you've figured out a quick & easy way of getting around it (like momentarily taking it out of T/H), then you're doing the right thing.
the 03 I have does the same thing down hill, @3000 rpm's, if you touch your brake's it will over rev. the best way I've found too get it out is floor the gas for just a second.
I leave t/h on because over 60, unless you look @ the dash, you cant tell it on or off, unill you slow down under 55 mph T/H does not down shift. That when I lock out the O/D with the t/h on seams too work good for me ENJOY
I have an '03 as well and in T/H mode, the overdrive doesn't kick in until over 57 mph as stated above - unless I am accelerating then it stays in 4th until I level out. I have the over rev problem too when towing - not even necessarily when I touch the brakes. The truck just senses the hill and downshifts. I tried to floor it, but it doesn't help - I just temporarily disable t/h mode until I am at the rpm I want. I usually downgrade a little slower because I have a 28,000 lbs loaded trailer and I just ride the exhaust brake all the way down the hill.
tow haul mode the 03 I have has a 4 inch exhaust with a tuner set too 40 hp up. However their is no exhaust brake. This will be the next step. gross combined load is around 23000# that's trailer and truck. Hope the exhaust brake will help with the down hill's good luck mike
