Overview & Reviews

The Sierra gets a revised look this year that includes a new front fascia, revised side moldings and optional multifunction, fold-away mirrors. On the inside, GMC has added new seats, a more comprehensive driver information center, a redesigned instrument panel and optional dual-zone climate control and satellite steering wheel controls. On the hardware side, the standard 6.0-liter V8 gets electronic throttle control as well as the ability to run exclusively on Compressed Natural Gas (CNG) or a mix of CNG and gasoline. Other upgrades include an improved Insta-Trac part-time four-wheel drive system for reduced service costs, a more efficient starter for the 8.1-liter V8 and a revised headlight switch that allows drivers to turn off the daytime running lamps.

• Powerful drivetrains, roomy interior, numerous available amenities.

• Spotty build quality, cheap interior materials.

User Reviews:

Showing 1 through 10 of 26.00

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  Bobs GMC - 2003 GMC Sierra 2500HD
  By RBob - November 5 - 10:00 am

  Drove this GMC across the country, many mountain roads and off highway. One of the most fun vehicles I have driven and I absolutely love the Turbodiesel and Allison transmission combination. I have had zero problems with this truck, you would think it was made in Japan for the quality.

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  Still smiling... - 2003 GMC Sierra 2500HD
  By brian0105 - June 11 - 10:00 am

  I researched long and hard when deciding on the $$ for the Duramax/Allison combo. Man am I pleased! It pulls my travel trailer like it wasnt even there. MPG has been better than my previous Firebird. Comfort is much better than I expected for a 3/4 ton. Looks? Man, you cant beat the Fire Red color! Dont know what it might take to wipe this smile off my face!

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  Excellent Duramax Diesel! - 2003 GMC Sierra 2500HD
  By Dave Hardin - November 14 - 2:00 am

  Dont want to spend to much time here, but if your thinking about buying this vehicle w/ this motor, all I would say is "do it". It awesome!

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  Fuel Economy - 2003 GMC Sierra 2500HD
  By Chevy Man - August 19 - 1:53 pm

  Ive had my 2500HD for just under a year now and I LOVE it. The only problem I really have is its fuel economy. I average around 14 mpg, but where it lacks fuel economy it makes up for it in power. I haul around a skidsteer on a 14 ft open trailer. The skidsteer weighs more then my truck but still no problems pulling it. The fuel economy doesnt really change weather your hauling or not. I just purchased an SLR performance chip that should do the trick. This truck is perfect for anyone with the money to pay for gas.

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  ?? - 2003 GMC Sierra 2500HD
  By Ralph gallo - May 17 - 10:00 am

  this is great truck ! no question about it .

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  Cant wipe the grin away - 2003 GMC Sierra 2500HD
  By D/A Guy - March 11 - 10:00 am

  Only service problem was the Service 4WD Problem as well. New module fixed problem. No other problems since. I found the ride to be very comfortable especially for a 3/4 ton. The room inside accomodates the family and kids with room to spare. 6 adults can ride in comfort with good leg and shoulder room. Milage is great for the power and weight. My average milage to-date is about 19 mpg over 17000 miles. The transmission is absolutely incredible and is what makes this truck exceptional. It handles heavy trailers with ease. I have yet to use all the power the Dmax puts out. It is without a doubt the best truck I have owned.

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  Hot Duramax - 2003 GMC Sierra 2500HD
  By J. Carroll - March 11 - 10:00 am

  This duramax is bad to the bone added bully dog 75 hp system to the truck now get 19.6 in town and 23 on the highway. pulled my 30 ft 5th wheel RV thought Colarado never missed a lick passed everything on the road and still averaged 13.7 mpg. Truck will white smoke the tires through 3rd gear and out run a new 6.0l Powerstroke no problem.

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  Too Much - 2003 GMC Sierra 2500HD
  By JailDoc - January 7 - 2:00 am

  The 8.1L, Allison Trans, this vehicle is beyond awesome, lousy milage but that is what was expected. Pull or tow anything, fast as hell, acceleration is neck snaping, stable anywhere you take it. So far no problems like my last GMC (ABS pump went out), the dealer is lousy, cant trust a thing they say. Time will tell.

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  nice truck - 2003 GMC Sierra 2500HD
  By bobby56 - August 18 - 10:00 am

  the truck is absolutely awsome. i had a 2002, same truck, traded it for the same payments and love it to death. its stong as an ox, both in horsepower and towing. (ford who?)

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  Nice for towing - 2003 GMC Sierra 2500HD
  By john gentry - June 19 - 6:30 pm

  This truck was bought for towing and does a great job pulling our fifth wheel camper.