The Gasser thread


Staff member
Who all tows with a gas-fueled tow vehicle?

I have a 2018 F250 with 6.2L and 6R100 trans. Good unit for what I do with it.
I am towing with an 03 avalanche 1500. Considering another truck now.
I assume your Avalanche has the venerable 5.3L? How much does your trailer weigh and how does your truck do pulling it? How has the trans held up?
5.3 with 3.73:1 gears, I also have a canned "tune" for about 20 more hp.

Really needs the 4.10:1 gears.

Trailer is 5500 or so dry. My trans has been rebuilt heavy. Rear end has been rebuilt.
I run a 140wt gear oil on the rear.

I run a giant tru-cool transmission cooler which I highly recommend.
It's a 40,0000lb gvw rated cooler
Model LPD-47391

It's thick, and even on steep inclines it stays under 180f. When towing. When not towing it runs about 118-130f.

Truck handles it fine as the avalanche is heavy. Needs more hp, lower gear( higher ratio).
I'd like more gears as 1st to 2nd is a wide ratio. I only have 3 gears other than OD.
What do you attribute the needs to rebuild both the trans and diff? How many miles total? Since you're a BITOG member, I'm sure you change your fluids.
The truck was used by the previous owner for dropping boats in the water. I have 84k miles on it. I only tow with it so all 84k miles are towing. I do change fluids but the rear end developed a whine at 81k miles, that I feared towing with. I think there was water intrusion at some point before I owned it.
So I had east coast gear rebuild it.
The transmission did not have a factory cooler on it.

When I went to drop the pan for a fluid change , the bolts that were open on the top of the trans case we're so corroded that they snapped off.
So with several bolts snapped off , on a transmission that had towed a lot with no cooler, I decided to just have it rebuilt. I could afford it, and it eliminated worry about an on the road failure. And even if I get a newer truck, I'm keeping it or giving it to my son.
Last edited:
I can imagine that the 1/2 ton chassis weren't designed with a 100% towing duty cycle in mind. That probably explains why the differential would be worn. We do have an engineer here who happens to know a pretty fair amount about differentials, maybe he'll chime in. :)
Back to the OP's topic, if GM would have had the 6.6L gas when I went shopping for our truck, I'm not sure I would have gone with the diesel.
Back to the OP's topic, if GM would have had the 6.6L gas when I went shopping for our truck, I'm not sure I would have gone with the diesel.
The new 6.6L gas GM engine appears attractive, at least on paper. I would rather see it paired with a 10spd trans to make the best of its torque band. I've not had a chance to ride in a truck equipped with one yet.
The Ford 7.3L has a bit more horsepower and a bit more torque than the GM 6.6L. The Ford gets the 10 speed, while the GM has a 6 speed.
I've done a fair amount of reading on the new 7.3L/10spd; reviews are good so far. Time will tell if the new engine and trans combo is well designed in terms of robustness. The 6.2L engine is renowned for good beharior and the 6R140 does well too. So the new engine/trans has a high bar to pass. I, and most heavy truck buyers, value reliability and longevity over a HP war anyway. I don't have to be the fastest to the top of the mountain; I just want to get there safely, over and over and over again.

IMO, GM is missing the boat by not updating to a 10-spd for the 6.6L gasser; gas engines need the benefits of smaller gear jumps even more than a diesel to stay at or near peak torque. The 6.6L gas GM motor has a smaller, narrower torque band than the Ford gas engines.
The Ford 10R140 10 speed transmission is standard on the 6.7L diesel and the 7.3L gasser. If it can handle the torque of the 6.7L, then I would expect the trans to last almost forever behind the 7.3L gas.

I would bet GM will release the 10 speed behind the 6.6L gas, as I'll bet customers are asking GM, why not the 10 speed? Who knows, maybe they can't make them fast enough right now, as the 10 speed is going into so many vehicles. I would sure hope GM would do like Ford and put the HD 10 speed designed for the diesel behind the 6.6L gas like Ford did with the 7.3L gas.
I tow with a 2017 6.0/6L90E. I came out of a 2002 6.0/4L80E. Both trucks have a 4.10 rearend.
With 2 extra gears, more HP and more torque, the 2017 tows much more comfortably then the old 02.

The 7.3 is a beast. Fastlane Truck did the Ike with it and it destroyed the Chevy. The Chevy needs an updated tranmission.
You know what else kills the Chevy...3.73 vs the Ford 4.30s.
It is like GM is trying to push you into a diesel.

The 6.2 Ford and 6.0 GM. The Ford with 4.30's, The GM with 4.10s were within a minute of each other on the IKE

The 6.4 Dodge with 6 speed was 2 to 3 minutes behind those.
Last edited:
Having said all that both of my 6.0s have been rock solid towing all over the west coast to include Lookout Pass, 4th of July Pass, the continental divide and other not so large ones but long like Vantage in Washington state.

Heck for years I towed with an 89 GMC 1 ton 454 TBI. Every pickup on the market now to include some of the normally aspirated V6 ones could out tow that, but it always got me everywhere safe and was reliable doing it.