How heavy does a load need to be to utilize the Tow-Haul mode? I reguarly pull a 3k load and tried the Tow-Haul mode yesterday. It didn't seem to want to shift gears as it should as the rpm's were stuck at 2100 while going 40. I would think that after staying in third gear for a while it would have shifted to fourth. Again, the load is only 3k.

How heavy does a load need to be to utilize the Tow-Haul mode? I reguarly pull a 3k load and tried the Tow-Haul mode yesterday. It didn't seem to want to shift gears as it should as the rpm's were stuck at 2100 while going 40. I would think that after staying in third gear for a while it would have shifted to fourth. Again, the load is only 3k.

I like to use the tow-haul mode all the time with or w/out load....Seems to be shifting normal.
Read this, I got it from the Allison Website:
. Tow/Haul vs. Normal Mode - What's the difference between Tow Haul and Normal Mode?
A. Tow/Haul (T/H) shift mode significantly changes the transmission's shift pattern to reduce shift cycling and to deliver better performance, control, and cooling when towing/hauling heavy loads. For instance:
Upshift points are raised at light to mid throttle position to use more of the engine's available power for accelerating.Downshift points are raised to enhance engine braking to help slow the vehicle.
During deceleration, the torque converter clutch (TCC) remains applied at closed throttle to much lower vehicle speeds to significantly improve the effect of engine braking.
During acceleration, the TCC is applied in 2nd range and remains applied in 3rd, 4th, and 5th. This improves the drivetrain efficiency and significantly lowers transmission sump temperature when towing heavy loads. In Normal mode, TCC generally applies only in higher ranges and is dependent on throttle position.

5th gear lockout and/or tow haul is nice for descending fairly steep grades without overuse of brakes. Works well loaded or empty. Most weight I ever tow does not exceed 5K so tow haul has not been used except for descending grades.

I'm with Lifted, I like to drive in T/H all the time and hear that turbo whistle and downshifting. It can be a bit of a pain at lower speeds when it won't upshift, with that light a load you could just as easily drive in normal mode and eliminate that. I use it when towing just about anything, I paid for it, I'm gonna use it. lol JJ

my sometimes seems lock and wont shift or shifts slowly in tow haul. i normally wont use it unless im pulling at least 5000lbs.

Every time I hook up a trailer I put tow/haul on...just help the tranny live a little longer. And long hills I put tow/haul on, seems to pull hills easyer IMO.

I just don't see how 2300 rpm's at 40 miles/hour with only 3k being pulled can be a good thing. Seems like it needs to be a heavier load to utilize the Tow-Haul mode.

Once I get into the high rpms (Long flat roads...nebraska) I take it off. But start and stop no matter the weight I put it on...IMO it drives better.

Once in awhile I also get annoyed in T/H mode when the trans wont upshift from 4 to 5 gear going 53 mph at 2300 rpms flat ground so I tap the T/H button and it will shift to 5 gear, then I tap it again to place it in back into T/H, the trans will stay in 5 gear until it is required to down shift again if the truck is lugging. GM and Allison programed these engines and transmission to shift and operate this way in T/H but if the engine noise and RPM get on your nerves bump the button and upshift.
If it down shifts again it for a good reason and let it be.
Love my truck
towing 26 FS Warrior with my HD inside
Southern Cal to Oregon twice
Southern Cal to Moab Utah once
Never a problem.....
Steve

I just don't see how 2300 rpm's at 40 miles/hour with only 3k being pulled can be a good thing. Seems like it needs to be a heavier load to utilize the Tow-Haul mode.

It took me a while to get used to the high rpm in T/H mode as well. Until I towed a 6k TT through Death Valley last summer. With the Allison in T/H mode going down some steep grades to the valley floor, the rpm got up to around 4800 at times--within Allison spec but still really high! I also use T/H down a particular grade here in town just to save the brakes a bit. As I recall, Allison says you can use the T/H anytime but expect the shift points to change.:D

If you don't need it; don't use it since it will cause more fuel consumption.

However, when I have my trailer hooked up, it's T/H all the way!

you have to be consistent if you use it because the tranny has to "learn" every time you do use it. i dont like to use it unless ive got a trailer because i cant remember to turn it on every time i drive. i get some weird shifts not consistently using it.