Transmission and mountain towing question

My duramax has the allison automatic transmission. Do you tow in the tow haul mode or use like 5th in manual out on the highway? Also on steep 6 ft downhill grades do you down shift to say third or leave it in the tow haul mode and let things work like they should? will the tow haul mode keep you slow enough going downhill without out using up your brakes?

Thanks, Tom

I always us the tow haul mode when I have the 5er on the truck. If you down a large hill and have the cruise control on say like 40mph the transmission and computer will keep the speed down and do all the work. Maybe someone that lives out west in the rockys will give you more advice. :!:

Same thing on my Ford, I keep it in tow haul all the time. It's great in the mountains 'cause it'll down shift to keep the speed down, don't have to hit the brakes and have them heat up.

Tow/haul all the time when pulling the trailer, that way you make use of the grade braking feature of the Allison.

Rhino, the whole cruise idea is great, I never thought about that. I don't have the Duramax, but I suspect it will work with any brand.

I traded my 2000 Dodge Diesel because of the sorry auto transmission. I then had a 6 speed for 5 years with an exhaust brake and it was a joy to drive and tow with. I now have a 2007 Dodge Diesel Mega-Cab with auto (I wanted the 6 speed but that is another story) and I am very happy.

Dodge has solved all the auto problems. I always use the towing mode. There are no heat issues, it locks the torque converter in 2nd, D and overdrive and with the cruise control set it will down shift and lock the torque converter to provide engine braking. I am happy with the current auto. I would highly recommend using the towing mode in any vehicle.

Bobby


Random Photo, Moonlight at the pier at the Outer Banks, NC

According to my Ford manual towing is be done in Tow Haul but you are never to use the cruise control. Why they recommended this I do not know. I know on flat ground the cruise works okay. Once it becomes hilly it sucks. That is my story and I am sticking to it.

Question. One thing I miss is the Overdrive lockout. When I tow there are times I would like to keep the auto tranny out of overdrive. Anybody ever see an after market kit that will do that?

Our dealer told us that we only needed to use the Tow haul if the transmission was shifting alot and to push it on going down hills to use the braking. I use the cruise on flat land like Nebraska.

Poetagie1968:
I use the Tow-haul & cruise control in the mountains all the time. I try to keep the RPMs up to keep from it shifting in and out when going up the MT.
When coming down hill, I make sure that the speed is set at the top. It will hold it to what I set it to. Like coming down Black Mt. on I 40 in NC, I set it at 35mph and it hold it and do not have to use the brakes at all

I always use the tow haul mode when towing. I tried it one time without and the trany temp rose pretty high. I leave it do what it was designed to do. Very pleased with the tow haul mode and grade braking.

KH

Most of my travel is in the intermountain west, lots of mountains. I always use the tow feature when hooked to the Cat. No appreciable difference in fuel mileage when I checked. Use the cruise on the flat-lands. Gotta love the Duramax/Allison combo!

I found that when on level running I get better mileage in Non tow mode, but when it starts to get hilly or bucking a headwind I use Tow mode. Tow mode seems to stay in a lower gear longer than need be when on level. Always use cruise control when I can. Overall average after pulling WC for 40K+ miles is 10.8.

I am the exact opposite. Tow Mode seems to find overdrive as soon as possible and appears to lug the crap out of the engine. I n the hills forget Tow mode.

Must be the differences between the 4spd and 5spd. No where in my manual does it say not to use cruise control in tow/haul mode, if fact it eludes to the fact of t/h mode automatically retarding on downhill runs if in cruise. I use that feature all the time. Now looking to see how the new 6spd handles it, ANY day now!

I don't have the Dmax, but my old 7.3 and the auto. I can lock out OD on the column. I have a few tow tunes that work like the newer tow/haul modes except they don't magically downshift on the tap of the brake. I have an exhaust brake tune that closes the warmup butterfly and restricts the exhaust and increases the trans line pressure. It works great. I manually downshift to 2nd if the grade only permits a 45mph speed. It holds back great. In 3rd (1:1 drive), a 6% grade doesn't hold back the truck without tapping the brakes.

The 5 speed auto manual does state that. I wonder if there is a way to shorten the lag. That would help. Also having the lock out button would be great. Just need to find a kit. Talala - Your auto tranny should be the same as mine with some upgrades. We both should have 5's. The main reason they took the button off was for fuel mileage. The unfor thing is that with the stretch bolts on our heads the head gaskets take a beating from lugging.