Towing with 10 speed Allison

[ahill261]

To all the GM diesel trucks with 10-speed Allison transmissions:

I am considering buying a 2021 GMC 3500 diesel. It shows a 10-speed Allison matched up to it. The top three gears are overdrives and I was wondering if, will pulling, the truck is constantly "searching" for the correct gear and if it is distracting? I appreciate your honest answers.

[Grumpy]

Originally Posted by ahill261

To all the GM diesel trucks with 10-speed Allison transmissions:

I am considering buying a 2021 GMC 3500 diesel. It shows a 10-speed Allison matched up to it. The top three gears are overdrives and I was wondering if, will pulling, the truck is constantly "searching" for the correct gear and if it is distracting? I appreciate your honest answers.

It shouldn't if you use Tow/Haul mode.

[Lake Huron]

I know it's not comparing apples to apples, but I drive a 2020 F450 utility truck with the 7.3 gasser and a 10 speed trans. I dont like it. It constantly skips 2nd and 4th gears. If it's in 3rd and you need go power now, it wont downshift. It stays locked in 3rd and a second or two later it takes off because its finally built up some rpm and power. Again, I know it's not apples to apples but driving highway speeds in a head wind, flat ground itll stay in 10th. Get to the overpass hill climb itll lose some speed and drop a couple gears, shift into 9th and sometimes have to downshift back to 8th to gain the speed back it lost again and then on the downside itll go back into 10th.
IMO, 6 speed trans is enough gears, 8 speed,... ehhh, 10 speed,... too many gears.
Being coupled to a diesel might be a completely different and enjoyable animal.

[CAG]

You are right it is not apples to apples. The Allison is a totally different animal that learns as you drive. It will not "search" once it determines your driving pattern. Drive it and enjoy it. The Allison is an amazing transmission mated with the the Duramax.

[Midnightmoon]

I found this interesting.

https://gmauthority.com/blog/2018/12...ly-an-allison/

[Sandybar]

I own a 2020 Chevy 2500 with Duramax Allison 10 speed. I tow a 9k trailer. Which is light for this rig. As far as “looking, jumping, or searching” for right gear, I have found that in tow haul mode is a solid option and so far with 16k miles it has so far preformed flawlessly. And the exhaust brake teamed with the Allison has preformed beyond my expectations. Don’t know how this unit will perform with a heavier load.

[Shokyle1]

All new transmissions learn as you drive. The new Allison (in name only). Is nothing special. Put it in tow/haul and lock out gears if you do not like the excessive shifting.

[Bourbonman]

I came from a 2015 Chevy 2500 Duramax with the 6 speed Allison and 100k miles with no problems and the 10 speed performs significantly better. Pulling from Phoenix to pretty much anywhere north we have a couple of stretches of steep grades of 2-3k ft in elevation gain and the 10 speed always feels like it’s in the right gear and power band simply left in drive in tow-haul mode where the 6 speed I would have to put in manual mode to stay in the right top gear to keep it from hunting while climbing up grades. I would not hesitate to recommend the 10 speed or the 2020 or newer GM HD trucks with the L5P Duramax. As much as I loved my 2015 the 2020 is better in every way.

[Ringneks]

I agree with the above post, I have a 2020 gmc, came from a 2016, this ten speed is awesome. I barely feel it shift, the wife even noticed the difference and that’s rare. I tow doubles up some steep grades here in utah and it performs flawlessly, mine does not search for gears, and I always tow in tow haul mode and let it do what’s it’s supposed to do.

[CAG]

If you are towing with an Allison and do not have it in tow/haul you are not using the facilities available with the transmission you have.