Let's talk GM 3/4 ton gas trucks for towing race cars in enclosed trailers

I currently tow the race car in a 20' enclosed trailer with a 00+ Ford Excursion with the 7.3 Powerstroke and 4 speed auto. I've had it about 4 years now and it's been totally reliable. The only time I use it is to tow with or the occasional Home Depot run. Occasionally I wonder if the grass is greener on the gas side of things. This is the only truck like vehicle I've ever owned. I've been especially curious about the gas trucks with 5 and 6 speed transmissions.

Things I don't like: - I think the 7.3 could benefit from another gear.
- Drives like a Ford truck.
- Diesel smell with the windows down in the summer.

I understand that the GM trucks drive a bit more car like due to the front suspension setup and steering system. I also understand the the 6.0 and trans combo tows reasonably well and gets reasonable MPG.

With the enclosed trailer, my MPG is nowhere near what it was with an open trailer. With the open trailer, I'd get 16-17 consistently. Now I'm closer to 11 which isn't too far off what a gas truck would do according to the interwebs.

What should I realistically expect for MPG with a gas GM truck? What are the problem areas? How much mileage can you realistically get out of the drivetrain before it starts wearing out?

Thanks.

Most 3/4 tons come in regular and heavy duty flavors. Get a heavy. Look for 8 lug wheels. The regulars are often not much more than beefed up 1/2 tons. Then again the heavys are nearly 1 tons these days.

The Allison trans in the GMs is awesome. I have a 1 ton 4wd with the duramax/Allison combo and love it. A friend has a 3/4 ton 4wd with the 8.1 gas/Allison combo and is real happy with it as well.

I can't really speak to the problem areas as neither of us have had any major issues other than the diesel injectors on mine, which is expected on the duramax. I have around 134k miles and he has around 200k I think.

I drove a brand new 2WD 2005 Silverado 2500 HD (GMT880) back when I worked at my uncles shop. I once towed a heavy wooden runabout boat from Marco Island, FL to Chicago. The drive down there and back was roughly 2600 miles. I really enjoyed that truck. It had the 6.0L with the 4L80E trans. It towed great with that boat. We pulled car trailers all the time, it had no problems.

If that's the era of truck you're looking at, expect low to mid teens in mileage when driving unloaded.

I just want to listen in.

I see them doing that all the time. Towing racecars in enclosed trailers, that is.

You have a known quantity in your truck, in that you've owned it for 4 years and worked out the kinks. It also is a 7.3L powerstroke, which is insanely valuable. Overall, you can't get much better than your current tow rig.

However, you are right about the newer 2500hd gms (2007.5 and newer).

I recently picked one up. It is a great truck, hauls up to its 12.5k towing capicity through the mountains no problem.

I like mine. The 6 speed without a tune sucks until you start towing. When towing, it is awesome. These trucks REALLY need a tune to bring out their full potential.

My mpg has been ok. I can get 13L/100km on the highway at 105km/h unloaded. Towing is anywhere from 15-20L/100km (15.5-12usmpg). Towing at full load or with an enclosed, I have no doubts it would be single digits (probably around 9usmpg).

I would suggest one if you need something more civilized over the excursion. They are good. But understand you will need to get used to reving the truck (it pulls to 6k rpm and the motor makes peak torque at 4k rpm). GET THE 410'S. If you find you don't need so much rear gear, put bigger tires on it.

You will never hear me say that the grass is greener on the gas side of diesel. Ew.

But, I do enjoy the smooth, quiet ride of my neighbor's F250 gas. I have a personal preference for Ford; fit and finish, interior quality, assembly quality, etc. Its just a better-built truck in my opinion. Both of the chevy's here (04 Dmax and 08 Dmax) rattle and buzz. The suspension is stiff and rattles and creaks. The 04 has already had the driver's seat reupholstered because of thin, cheap leather. The stereo likes to automatically start playing a CD sometimes. I strongly prefer Fords, but to each their own.

As far as drivelines, the 8.1L and Allison is hard to beat. You'll likely get single-digit MPG while towing and only mid-teens empty. For as much as you tow, I wouldn't go crazy with big engines though. A 5.4L Ford or a 6.0L Chevy would do just fine. No reason to get a complete gas-hog for 8000 lbs of occasional towing.

Most of them have been very reliable for the last decade or so. Prior to that, none of them could make a transmission worth spit. Many years of the Ford 5.4L had issues with the long-reach plugs seizing in the heads. Any of the 2000's Fords with coil-on-plug will be nightmares. One starts to go and there is really no way to identify it without an oscilliscope at a Ford garage, but if you replace only one, the next weakest will fail. Best to just pony up the dough and replace them all. Actually, best to just avoid them.

Just curious... selling the Excursion? We should talk.

I have a 2002 2500HD crew cab long bed with the 8.1/Allison/4.10 combo. It's a beast. I would say it tows so well you don't know anything is back there, except that it actually drives better with a load. Best mpg I ever saw was 12, and that was unloaded and driving slow on the interstate. 10 is much more typical, but it doesn't really get worse than that either. 120k on mine, the last 40k of which are on me. Been very reliable, has held together well, etc.

Another thing I should mention... the 7.3 should be getting much better than 11 mpg towing, and a gas engine (despite being lower on torque) won't get you 11 towing. I got 14 towing 10k with both of mine. That plus the diesel smell says fuel filter leak to me. Its a common issue. The aluminum housing for the fuel filter gets pinhole leaks.

Not trying to convince you to keep the Excursion, but you can almost double MPG with a 7.3 compared to a gas truck. If you're not getting 20-22 empty and 13-14 towing 8-10k, something is wrong. Just doesn't seem like the fix is to get a gas truck in this case. You have a perfect tow monster right now.

Edit: in their defense, mine were both mildly modded. One had a valve body upgrade and a switch to keep the TC locked at all speeds above 35. The other had a chip.

As much as I like my 2500HD, the 7.3 Excursion is a towing unicorn. Might be worth seeing is Curtis is on to something with that fuel leak theory.

I tow my 20' enclosed trailer with an 08 Silverado 2500HD with the 6.0 gas engine. Its not a rocket but it gets the job done. The biggest downside is the 8 mpg it gets with the trailer attached doing 55-65 mph.

atm92484 wrote: I tow my 20' enclosed trailer with an 08 Silverado 2500HD with the 6.0 gas engine. Its not a rocket but it gets the job done. The biggest downside is the 8 mpg it gets with the trailer attached doing 55-65 mph.

And if he's only getting 11 mpg, he's still besting your gas MPG by almost 40%. Still cheaper on fuel and half again more torque.

Thanks for the input.

I can get around 18-19 empty if I'm careful with speed. Usually, I'm not careful so I see 17 ish MPG. Less if more city driving.

Mileage took a huge dump with the enclosed trailer. I don't smell diesel fuel. I do smell unfiltered exhaust from the diesel - which stinks. I think the turbo may need some help. Impeller has a bit of play. Response/power isn't as lively as it should be in the 1,500 - 1,900 rpm range which leads to more frequent downshifts while towing.

atm92484 wrote: I tow my 20' enclosed trailer with an 08 Silverado 2500HD with the 6.0 gas engine. Its not a rocket but it gets the job done. The biggest downside is the 8 mpg it gets with the trailer attached doing 55-65 mph.

The 6.0 was the biggest disappointment in an engine I've ever had.

Yeah, it had torque. Yeah, it could tow.

But that fuel economy was abysmal.

amg_rx7 wrote: Thanks for the input. I can get around 18-19 empty if I'm careful with speed. Usually, I'm not careful so I see 17 ish MPG. Less if more city driving. Mileage took a huge dump with the enclosed trailer. I don't smell diesel fuel. I do smell unfiltered exhaust from the diesel - which stinks. I think the turbo may need some help. Impeller has a bit of play. Response/power isn't as lively as it should be in the 1,500 - 1,900 rpm range which leads to more frequent downshifts while towing.

You're not going to like what I'm about to say, but $2000 worth of upgraded turbo, exhuast, and a chip will pay for itself pretty quickly. Improved MPG, more torque.

... and that exhaust smell isn't stinky, its rose petals and sunshine.

The 6.0 gets a little better mileage unloaded than the 8.1, but way worse loaded. 10 - 11 mpg pretty much regardless of load or speed.