I will soon be towing my 5er, what gear do most of you use? My 5er is 26
ft. long, weighs 6k fully loaded. I know I need to use to tow/haul button, but am mostly wondering about the gear selection, do i tow in D and just use the t/h button, or do I need to shift to M and select one of the higher numbers and still use the t/h button, I will be driving mostly in Michigan, at least for this summer, so most of my hauling will be flat terrain.


2006 Duaramax/ Allison shortbox bought used 6 weeks ago, all stock

Basically all you need to do is use D and the Tow/Haul button. The D/A should handle the 6k trailer just fine.
If you'll be going down some really steep hills you can use the manual setting (M) and T/H mode to control your speed by dropping down through the gears from 6 - 5 - 4 - etc. as needed.
In my experience the allison is programed to do all this in the D setting and works just fine.

Just put the tranny in D and push the tow haul button and step on the loud pedal. You won't even know the trailer is even there, especialy if it only weighs 6k loaded.

Just put the tranny in D and push the tow haul button and step on the loud pedal. You won't even know the trailer is even there, especialy if it only weighs 6k loaded.
Yeah, that's NOT alot of weight at ALL. Keep yourself and trailer between the lines and set the cruise you'll have a great drive!
If you set the cruise while going downhill the truck will do the grade brake thing and you may not even have to tap the brakes.
Use the TowHaul and keep it in D unless you want to play with it.

When you are towing up a grade, it is best to use the tow haul switch and put the tranny in m mode and put it on 5. Sixth is overdrive and is hard on the tranny. Flat terrain d would probably be fine. I dont like putting too much of a strain on my convertor and od gear clutches. I tow daily 200 miles from 6k to 12k lbs and only use m.

When you are towing up a grade, it is best to use the tow haul switch and put the tranny in m mode and put it on 5. Sixth is overdrive and is hard on the tranny. Flat terrain d would probably be fine. I dont like putting too much of a strain on my convertor and od gear clutches. I tow daily 200 miles from 6k to 12k lbs and only use m.
Well 5th is actually overdrive as well. In California legally you tow at 55 mph, and if it's not DEAD flat for a few miles my truck in tow haul wont get out of 5th gear until you run it up to 63 and then slowly slow back down. It'll then stay in 6th gear and when it needs to it WILL Shift back to fifth I've seen. I dont know if this guy's truck will ever shift down with only 6k. I'm at 9k empty with my living quarters.
I myself used to shift it, and watch everything until I just realized i'm not doing as good a job as the truck is if i just leave it alone. LMAO.
I WILL shift down going down a hill, and decelerating for an offramp, I do that often and find it helps alot. After i slow down or hit the bottom of the hill, back in D it goes.

If you read the manual it will tell you don't even bother with tow\haul until 75% of the GCWR is met as fuel economy will suffer.

That is somewhere around 15,500 lbs which you are at about 13500 lbs. I would leave it in drive and I bet you can hold 60MPh going up many a hill downshifting only into 5th if at all. Tow\haul becomes a real pain in the but if your in any kind of traffic or doing around town driving, constantly downshifting!

Your not even straining your truck. If you want to see cooler trans temps then switch over to Transynd but leaving it in D and for that matter on cruise will make you a real happy camper. Set it and forget it so to speak!

I'd be careful, when not using tow/haul. tow/haul locks the torque converter in the low gears and significantly reduces the transmission temp when pulling big hills in 4th. You will over heat the transmission by pulling a hill in 4th with tow/haul turned off.

My open car trailer is similar weight to that, loaded.

You'll know it's there, but not by a whole lot :)

Just put it in T/H, put it in D, and go with it. Let the grade braking do it's thing. I've come down Donner pass (7000 ft to sea level over about 60 miles) on I-80 with that combo and barely had to touch the brakes, grade braking built into the trans did all the work!

Just put it in T/H, put it in D, and go with it. Let the grade braking do it's thing. I've come down Donner pass (7000 ft to sea level over about 60 miles) on I-80 with that combo and barely had to touch the brakes, grade braking built into the trans did all the work!

Just curious Impala, how did you truck do going UP Donner???

Just curious Impala, how did you truck do going UP Donner???

Basically, the only time it even downshifted out of 6th was if someone in front of me did something dumb to cause me to tap the brakes. Just set the cruise at 62 MPH (to get into 6th) and truck right along as if the hill isn't even there!!! :D

FWIW, doing that same 62-63 MPH on a trip to SoCal last month towing same trailer but a lighter car (car + trailer = closer to 4500 lb) we got almost 17 MPG!

On a recent trip pulling my 28.5 fifth wheeler I checked my mileage using t/h mode and not using it on similar terrain. I was surprised to learn that I got better mileage using the tow haul mode. The motor ran cooler and the tranny temp was a bit lower as well.
As others have said, put it in T/H mode, use the cruise and enjoy the scenery.

Put it in T/H and let the Allison figure out what gear to use...that's why we paid all that extra money.