First Drive Review: 2011 GM Heavy Duty Pickups Summary, Part 5

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Other Notable Items

Like Ford’s Power Stroke, the Duramax uses selective catalytic reduction to scrub nitrogen oxide emissions down to no more than 0.2 grams per horsepower/hour. It’s a new EPA requirement as of Jan. 1.

The SCR system uses diesel exhaust fluid, or DEF. The urea-based solution (32.5 percent industrial urea and 67.5 percent deionized water) is held in a 5.3-gallon storage tank and injected as a fine mist into the Duramax’s hot exhaust gases. The heat turns the urea into ammonia that, when combined with a special catalytic converter, breaks down the nitrogen oxide emissions into harmless nitrogen gas and water vapor.


The DEF refill point for the Silverado HD is mounted under the hood of the engine instead of next to the diesel refueling cap on the side of the cargo box, as it is on the 2011 Super Duty.

We’re told to expect about a 5,000-mile range on DEF, but we couldn't see how much we used in our heavy towing and hauling exercises because we moved from truck to truck quickly. We’ll have to wait and see how it goes once we do an extended drive later this summer with a Sierra HD.

The GM HD pickups are also B20 biodiesel compatible, able to run on a blend of 20 percent biodiesel and 80 percent conventional diesel fuel.


After sampling a wide range of 2011 GM HD pickups in varying towing and hauling situations, we’re very impressed with the changes that GM has made just three years after the last major revision to these trucks.

With towing, hauling and power ratings that surpass almost every truck in the segment, GM has gotten closer to challenging Ford’s best-selling F-Series Super Duty lineup than ever before. The new frame, ride and handling and diesel powertrain improvements have class-leading performance and are certain to work well in almost every situation we can imagine, unless you’re a swamp road logger and need a solid front axle for that extra bit of off-road capability.

We only wish that GM’s trucks received more extensive exterior makeovers and all-new high-quality interiors with modern information technology.

What We Like

  • 6.6-liter Duramax V-8 diesel and Allison six-speed automatic transmission are better than ever
  • Standard diesel exhaust brake is best in class, along with best-in-class cruise control that makes long-distance towing and hauling a snap
  • Bigger wheel brakes have best-in-class feel and add confidence while towing larger loads than ever before
  • Newly available 18-inch and 20-inch wheels
  • Confidence-instilling ride and handling characteristics on all pickup models
  • Mobile Wi-Fi is a productivity enhancer while you’re on the go
  • Trailer sway control for SRW HD pickups
  • GMC Sierra Denali HD is a classy workhorse


What We Don’t

  • Big louver on the hood of the Sierra HDs has to go. Should be a deletable feature.
  • Interior fit and finish should match the excellent driving performance
  • Revised six-speed 6L90 transmission needs more calibration
  • Lacks a rich driver information computer like Ford’s productivity screen and Ram’s in-dash LCD

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Wow , this is the best of the best now for sure. Love the GMC body and grill. Heavy Duty trucks at the top of the game is what these new GM,s are.

Very nice trucks! I do agree about the GMC louvers though; terrible design choice. In my opinion they look as if the louvers on the 07 chevys were pushed together and stuck on the middle of the hood. Great trucks though, I'd love to drive them!

The new GM hd trucks look pretty good I wish I needed a new truck .

Good write up Mike! Did you get any indication on fuel economy with the LML? I missed it if you mentioned it in the review.

@Alex: I'm purposely not talking about or measuring fuel economy until we drive all 3 HD pickups during the Shootout or at least during a week long road test. The hilly terrain we were on for the GM trucks was very different from the mostly flat ground (except the trailer towing portion) that we drove the 2011 F-Series SD truck across. The 2010 Ram drive was about in the middle.

Mike just wondering what u ment by -------> the power difference between the all-new standard Ford overhead cam 6.2-liter gas V-8 and GM’s overhead valve 6.0 is much narrowed ? is the 6.2L Ford still behind this 6.0L? and for the 3v V10 is behind the 6.0L ?

@Cory: Sorry that was unclear. The GM 6L is rated at 360 hp/380 lbs-ft. Ford's 6.8L V-10 was/is 360 hp / 457 lbs-ft (!!). The new 6.2 is 385 / 405.

There's much less difference in torque between GM's and Ford's standard gas engines. You can feel it with a trailer on the back. The 6.8L was always a monster and we said that in our first drive review of the 2011 Super Duty and in the 2007 HD Shootout, when it beat the 6L.

I've changed power to torque in that sentence. Thanks for asking!

Why spend all of the money to fix only half of the problem?
HD 4x4s need SFA.

The rest of the truck seems solid though. Not a fan of the interor design, but the exterior, though mild, is a welcome refresh.

Mike, How much does that small excavator weigh. It and the trailer?

@Robert Ryan: Approximately 10K-pounds.

Time will tell how well it by how many you actually see on job sites and at campgrounds

So Mike, When will we see the heavy duty shootout? Since no information about the Ram hd's is available to the GP. Unless you count the chassis cabs.

@ty: We're doing the HD Shootout next month. Come watch the first day on July 12 at Milan Raceway in Michigan.

@ Mike,

I hope this shootout will have these trucks at their max towing limits so we can see some real world capabilities!

I hope you dyno all the trucks, would be interesting to see how accurate the numbers are. How does the Denali interior compare to the King Ranch? With builds like these, its going to be a very interesting shootout. I hope Ram has something to bring to the table, as it looks like the Ford and Chevy(oops) will be the real competitors.

Thanks for the excellent write up. Are you planning to wait for the 2011 Ram HDs? Then the comparison is all the same model year. A friend of mine works at a Ram/Jeep/Chrylser dealership and has mentioned that the 2011 Rams may be getting a change and going to urea injection as well to improve fuel economy, as well as, a tune. I am not referring to the CC. Have you heard anything similar to this?

What gears did the 6.0L Denali have in it?

@Daniel: The Sierra Denali had a 3.73 final drive ratio.


Nice write-up. I wish I had known you guys were doing this -- I live in Southern PA and spend time in Western MD (Frederick). As a matter of fact I was at BWI airport on 6/7 and 6/11!

Who will be driving the trucks in the shootout, will it be, independant drivers, or every manufacturer will drive it's own truck?

@Andrew: We'll have the same driver from our staff (TBD who it will be) drive the trucks. Ricardo Corp. is once again instrumenting the trucks to collect data independently. Manufacturer reps will be on hand to watch and answer questions.

great review mike!

GM has defintly stepped up their game in the heavy-duty segment...

the most powerful diesel on the market plus the Allison tranny and a brand new frame... Sounds like a beast to me...

@ Mike - good review. I agree that the Sierra and Silverado interiors need some work. I like the looks of the Sierra. The plastic hood thingie is a joke. It can't wait for the HD shootout.
It's interesting to hear (literally) comments about the engine brake sound. I think Ford goofed by making their diesel too quiet. The viceral and auditory feel of a truck adds to it's driving pleasure.

Sounds like an awesome truck! i would kill a man for one of these new beasts.

Thank you for the answer.
One more question, On the 2011 GM HD cab and chassis, is it still fully boxed frame?

I take it that you guys drove CTF trucks?

If so, could that explain some of the fit and finish issues?

@John: Yes, they are captive test fleet trucks that will be used for marketing and training with dealers. But the fit and finish issues aren't new. I've seen them in the 1500 trucks too, recently. Head units and glove boxes seem to be the tough spots.

GM doesn't need all of the fancy gimmicks the Ford has to sell trucks. GM trucks sell on their merits. GM's have the better ride, better powertrain, and better capability numbers.

The 2011 GM trucks are the new standard of HD trucks. And that exhaust brake is a GEM. Once the new V8s drop...there will be no catching these trucks.

GM doesn't need to offer fancy gimmicks to sell trucks? Well why the heck do they bother running all those ads for Onstar? Gosh, can the fanboys just go away, so we can have a real discussion?

@p did you see the sales numbers

@mike levine we have an isuzu diesel in our fleet with the urea system on it . do you know if this is alot like the one on the gm trucks. we are having problems when they go on dirt roads. other than that these new gms look like some great trucks and that is coming from a ford fan.

@bobsled80: Sorry, I don't know if they are the same system.

@ Mike: Nice review. You really covered every aspect. Will offroad capability be a part in the new heavy duty shootout? Cause I'm a little bit worried about the new front suspension. Very nice, these new GM HD trucks.

front suspension on the GM brand trucks has never been as strong as it needs to be. That is one reason you could never put a plow on it.

My guess is unloaded it will be so so. Still to low to the ground though.

If you read all those articles about 2011 GM HD trucks, you will learn that it has ALL NEW chassis and suspension, and GM engineers actually designed these trucks to handle the biggest snow plow for C class that you can possibly get.


Jury is still out, but does look promising.

The only thing that isn't class leading on these trucks IMO is their interior.. Everything else seems fantastic.

I think this new frame will help them pick up some market share in the HD segment.

I can't remember where I read it but shortly after the last generation Silverado HD ('99 to classic '07) came out, it was mentioned that the cab and bed were raised a few inches b/c of the fitment of the Duramax diesel/Allison tranny, which is why the frame looks like it hangs so low.

But I could be wrong about this.

The new frame will not win them any contest in the HD segment except from Joe Homeowner who wants one parked in his front yard. C channel frames are preferred for aftermarket work truck boxes and whatever else you can think of that companies want to throw on the back of a work truck. I think GM may have shot themselves in the foot by doing this. Just my two cents.

Put it this way, half ton pickups are excellent pickups to have fully boxed frames (FBF) because you mostly do light towing, companies don't modify 1/2 tons to much, and you much more likely to go off road with these trucks where the stiffness of a FBF would come in handy. HD pickups on the other hand more or less are for one thing only, to tow heavy loads. You DON'T need a FBF to tow 20,000 pounds. If that were the case then how can class 8 tractor trailers do it only using C channel frames?

The commercial box-delete models come with open channel in the rear section of the frame. So that shouldn't be a problem.

Second, I don't understand the hate towars FBF, because, they are much stiffer and stronger for their size, and heaven forbid, the aftermarket add-on companies have to actually do a little bit of engineering to fit the new frames.

Third, yes, semi trucks use open C-channel frames, but they don't care much about rigidity or ride quality. Even see how much one of those frame twist under acceleration (yes I know they have like 2,000lb-ft of torque, but I'm willing to bet they would flex less if they were boxed. Also, you can make a C-channel as stiff as a FBF, but it will be larger, and heavier, but cheaper which is why bug trucks use that style.

If you ever get the chance to ride in a 2009 HD and a 2011HD back to back, I guarantee you'll love the stiffness of the 2011 because it rides soooo much better and feels much better, and yet didn't gain much weight because of the boxed frame.

So it would be as good as my 2004 F150? :)

So you're saying the 2011 SD isn't at good as your 2004 F150? I guess Ford is going backwards.

@Mike Is your shootout going to include the gas motors, or just the oil burners? Seems the oil burners are all the rage in the press and the numbers are impressive, but I can't afford the extra $8K+ for one. Fuel economy payback on the $8K is about 80000 trailering miles or 200000 empty miles. Yea, they drive nice and tow nice, and some folks NEED them for what they do, but those folks with a real NEED are few and far between.

@TF: We're testing both gassers and diesels configured identically in the three-quarter-ton class.

No Tim, now that the Chevy fans are saying boxed frame is essential (because obviously before this month, it wasn't important), that my 2004 F-150 must be good, because it ticks that box on the spec sheet. Pun intended.

I'm willing to bet that new GM HD frame is stronger than the the F-150's. Not saying the F-150 doesn't have a good frame, obviously the fully boxed is nice, but to say that this frame is only as good is false and you know it.

And now you're making fun of Chevy fans because they are saying a boxed frame is essential now, so does that mean, Ford thinks it STILL isn't essential on their SD trucks, when they apparently think it is essential on the LD trucks. That makes no sense.

Just because something is new doesn't mean it wouldn't have been nice to have it before. That's like saying, seatbelts weren't needed back in the 30's, airbags weren't needed in the 80's. That's just the way progress works. It would have been nice to have seatbelts, airbags, emissions controls, boxed frames in the 30's but they weren't invented yet.

Ford may have beat GM to the market with a boxed frame in the LD truck, but GM has Ford beat in frames in the HD class. And if you don't think a boxed frame is stiffer and makes the truck more solid, just read the article on here about the twisting the SD frame did when taken over uneven terrain.

Gosh Tim, get a sense of humor would you?

@ Mike: Are you gonna take these 3-quarter ton trucks offroad too? I'd like to know how this new front suspension in the GM-trucks perform offroad. Can't wait for the shootout.

Wonderful - the present GM's Silverado/Sierra is an impressive truck, that looks just great - I love its classic design, needs no changes!

When exactly is the shootout?

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