When to use Tow/Haul mode?

[psyco66]

Anytime a trailer gets hooked to my truck tow haul mode is on. I do not see a reason to turn it on and off when the trailer is hooked to it. The trans knows what it need to oppertate so let it do its thing. JMO.

[duramaxin14]

also tow haul basically increases pressure. Keeps the internails of the tranny running cooler

[executivehauling]

Am I dreaming or don't I get worse fuel economy with it on. I have no mod's( exhaust/air/chip ) done to the truck yet. The braking power is awesome from the tow/haul being on. I agree with a previous post, if you are doing a lot of start and stop, or up and down, you should probably have it on to keep it from kickin down, but if your on the flats, I'd turn it off and save the fuel. This truck runs awesome to say the least. My 08 runs somewhere around 1600 to 1700 rpm's at 65mph pulling 8,000 lbs. I notice a drop in RPM's when I turn the tow/haul off, not much but.... I paid $4.50 a gallon in Pittsburgh yesterday so..... I'd save when you can save. Just my .02 towards $4.50 a gallon

[psyco66]

My truck gets the same MPG with it toy haul on or off. I have checked a number of times. And that is with hand calculation.

[mr.mincas]

i haul a 53ft car hauler, 15-16000 lbs loaded, behind my 03 duramax, all stock except for a Superchips Max micro tuner, putting out an extra 90 hp and 140 ft-lbs trq. I only use T/H for slowing down because i found that on any bit of incline it would downshift if in T/H mode. T/H mode is great for heavy hauling in town i find tho because it doesn't lug the motor as bad.

[executivehauling]

Originally Posted by psyco66

My truck gets the same MPG with it toy haul on or off. I have checked a number of times. And that is with hand calculation.

Good stuff, I'll test it on my way to Houston next week, and see how I do on the way down.

[Durallymax]

I use it religiously.

Every time I have to slow down or stop I hit it. And every time even an empty flat rack is hooked onto it I hit tow/haul. All your doing is using a tad more fuel.

It keeps temps cooler because the TC is locked up so it isnt heating the ATF fluid.

I run 315s and my ally shifts fine. I have reprogrammed the shift points a time or two but got too carried away and havent messed with them again yet.

The biggest thing to remember is that the redline is 4500RPM on these motors so dont get scared when it downshifts and revs way up. Its just doing its job.

[Durallymax]

I also like driving in tow haul because It drives like a manual and i know it feels like its in a gear.

[pooh1949]

All said is true , except no one has said that when in T/H with the 6 speed it will never go into 6th. You can be doing 75 and switch your lever to " Manual " and you will see that you will be in 5th. (read the Allison booklet that comes with your owners packet).
I'll second or third the motion " wouldn't tow without it " to many pluses not to.

[Johnasara]

I often pull a trailer, it weighs about 10,000 lbs. My truck is also loaded with about 2,000 lbs of tools. I use tow haul on the highway but not in town. I have found the allison tries to slow down to fast in town.Every time you take your foot off the throttle.There is no speed limit in town over 35mph. I use a trailer breke controller that takes care of braking in town.I have not noticed a difference in mileage on the highway with or without it, I have not even noticed a difference in Rpms or fuel mileage. The truck gets bad/cty and bad/hwy mileage but is aproaching its gvwr in weight.