Borrowed my buddy's 2011 GMC Sierra 3500 HD Denali, DRW, with the 6.6L LML Durmax engine. I had a 44' gooseneck race car trailer in tow with two cars inside. GCW is right around 26K lbs. My usual towing combo is my 6.7L F350 Lariat with either a 24' or 28' tagalong trailer weighing in at 20K lbs (GCW).

I towed about 500 miles with the Denali. I have to say, anyone that thinks that GM doesn't make a good HD truck is off their rocker. I am definitely a Ford guy and prefer a Ford product, but the GM equivalent is equally a good product. I made some observations while comparing the two trucks.

Towing:
To be honest, this will be true for any truck that is a DRW and towing a gooseneck trailer. But this was my first experience with a gooseneck. The truck is extremely stable, very comfortable, and over bumps, you can't even tell that the trailer is back there. On a tagalong trailer, you'll feel some jostling and some oscillations from the trailer as it goes over bumps. The Sierra though was excellent for the tow.

Engine/Transmission:
Definitely lots of power out of the LML. The HP and TQ ratings are so close to our Scorpion 6.7s that you can't really tell any difference. The gearing however, well I'm going to have to go with the Ford on this one. It seems the Allison transmission has a shorter first gear ratio than our Fords, but the Ford seems to have more go off the line. I realize that there is a weight difference of 6K lbs, which is not insignificant. I think my biggest issue were the harsh shifts when the truck was under heavy load (both upshifts and downshifts) and the 3-4 and 4-5 shift. The truck just falls flat on its face when it does the 3-4 upshift. Same thing with the 4-5 upshift. Plus, not once did I see the tach below 1500 RPM. The transmission was quick to kick down a gear, despite my best effort at leaving it in 6th gear with the torque converter locked. On our trucks, I've never seen the torque converter unlock over 4th gear. On the GMC, it unlocks in every gear if need be.

One thing I did notice is that there is a lot of vibration if you accelerate hard from a stop. Just like in our trucks how there's a grinding noise if you accelerate hard while towing, same in the GMC. But in the GMC's case, the entire truck vibrates. Easy solution though, you just have to very gently roll on to the throttle. I'm sure sending 765 torques through the driveline isn't easy.

Also, despite having a manual mode and a button to shift the gears, there is no way to lock out gears like we can on our trucks. On one part of the trip, it goes through lots of rolling hills. My truck will constantly go between 5th and 6th gears. I usually lock out 6th gear and keep it in 5th gear the entire time. On the GMC, there was no way to lock out any gears. Going to manual mode meant losing my exhaust brake/trans downshifts, something I didn't want to do.

Brakes:
Both trucks brake very well. Never had any issue with initial bite, fade, or anything like that. The GMC's brakes are however touchy whereas the Ford brakes seem to feel more linear based on effort applied.

Exhaust Brake:
I've never had any complaints about our exhaust brake. It works fine for me. All the car magazines say that the GM exhaust brake is better mainly because of the transmission gearing. The 4th gear in the Allison is definitely longer than our 4th gear (despite ratios both being the same according to the specs...if they're right). So the truck has a wider range with which to grab 4th gear to hold the truck steady, whereas there are some speeds with our trucks where it's too fast to grab 3rd, and grabbing 4th is almost useless. That may explain why the truck falls flat on its face on the 3-4 upshift, probably because it's longer for the braking side of things.

Interior:
Ford wins, hands down. There were three of us in the truck for this trip. The two passengers were constantly battling for space. The back passenger was cramped when the front passenger moved the seat back. The front passenger would move the seat forward again and would long for more leg room. And the rear bench was very uncomfortable. There's also far fewer cubbies and storage bins in the GMC. The infotainment system in the GM is tragic. The interface is awful and the graphics are right out of the 80s. There's no turbo boost gauge, there's no oil temp indicator. There's a tiny screen in the cluster that has fuel economy information, odometer, trip meter, trans temp, and some of the truck settings. The freaking USB is inside the center console. If you wanted to plug in your phone to charge it, you can't even close the center console because it would crush the cord. Who thought that was a good idea? Only two airbags in the GMC, versus our six. Front seats were comfortable. I felt no fatigue from the trip. GM wins with auto down on both front windows though, but no auto up. But no grab handle on the driver's side A pillar to hoist yourself into the truck, unlike our trucks. There's one on the passenger side, but I needed one on the driver's side. Also, manually telescoping mirrors...really?

Fueling:
What a disaster. GM filler necks are a huge fail. They don't take the high speed nozzles. I learned the hard way, even after the pump clicked off, a BUNCH of diesel shot back out and went all over the place. On my next fill-up, I slowed it down toward the end, but still had diesel shoot out of the filler neck. If it's a "heavy duty" truck, it should be able to go where the big boys go and get diesel like the big boys get diesel.

Steering:
I think the GMC wins on this front. Sorry. I've never had an issue with my Ford steering. True, it takes more turns of the steering wheel and it offers no feedback and on-center feel is pretty vague. The GM steering ratio was definitely shorter so the inputs were more direct. Around turns, the effort would increase just as it should and the feedback was excellent. I don't think there's anything wrong with the Ford steering per se, but I think the GMC steering is a good way to go. With the GMC, it feels like you're driving a big, heavy car. With the Ford, it feels like you're driving a bus when it comes to steering.

Overall Impressions:
I am impressed with the GMC. Great truck. Very strong, very stable, very capable. The interior needs work, but I know GM will address that with the new models. Engine was great, and transmission was good. I think because the transmission learned how the owner of the truck drivers and it was trying to learn my driving style probably contributed to some of its confusion.

So yes, while I still prefer my Ford, the GMC is a great truck. There's just no denying that competition breeds better products. In this case, the competing product has a lot to offer.

Here's a picture of my rig from this past weekend.

 

Good review. We had an 2008 Duramax before getting this 6.7. I found many of the same comparisons to really appreciate the Ford product. Nice trailer he's got there!

 

Nice unbiased report

 

Jimax

I am curious about the weight you list on your 24 and 28 foot tag trailer
Did you say they weighed 20 Thousand pounds?

By the way great review we have both the GM and the Ford products in our company and you are spot on most of what you said

 

I does have a better car ride but needs serious updating.

I understand with the 2011's redesign the front end will last better now.

low slung frame to drag off road is a killer though.

 

Very nice review Jimax...

 

Sorry, the trailers themselves don't weigh 20K lbs. The GCW of truck/trailer with a tagalong is 20Klbs. Trailers themselves weigh in around 6K lbs and once fully loaded, are right around 10K lbs.

 

Good stuff Jimax, reps sent for an unbiased review!

I honestly wish most people would do stuff like this. Blind loyalty is never a good thing and it's always a great thing to evaluate the competition whenever spending money. I've always heard great things about the latest generation GM trucks, but your review puts it better in perspective.

 

Great report!

I drove a GM before deciding on my Ford and the biggest complaint I had besides liking the Ford better was that there was no knee room. I kept banging my knee into the console. It was better suited for someone under 6'.

They are, however, both nice trucks.

 

What brand race trailers?

 

Pace Daytona Shadow GT, dual 5200lb axles.

 

Ok I had a Pace before I bought the Gold Rush
The pace is a decent trailer but heavy as you know
What type of racing do you do?

 

We have the Shadow GT as well, nice trailer.

 

Club racing or amateur racing with National Auto Sport Assocation (NASA). I race a BMW M3 on roadcourses up and down the east coast.

 

They're the best of the best in my opinion.