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-
GMC CrewCab 4WD SLT with 8.1L /Allison - 2003 GMC Sierra 2500HD
By Gilbert L. - March 22 - 10:00 am600 miles and drive-by-wire trottle body left me stranded. Immediately after the dealership replaced with new trottle body, the 4WD Transfer Case Control Module misteriuosly went bad (RE: Service Bullitin Rel. 02/2003). Very poor Service Dept. at dealership. I had very bad experience with unscrupulous mechanic who falsely claimed work that was not performed. Suspension springs incorrectly installed by manufacturer.
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GMC 1500 HD - 2003 GMC Sierra 2500HD
By USA DAD - October 14 - 10:00 amMy truck gets about 15 miles per gallon, which is better than I thought it would. It pulls hay like it wasnt back there.
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Duramax and Allison are superior - 2003 GMC Sierra 2500HD
By Jim T - January 20 - 5:53 amI have owned this truck since new in 2003. Only in the last several years have I used it to its full potential. I have pulled a 10,000 lb fifth wheel to Florida twice and a new 12,000 lb fifth wheel to GA last week and I averaged a little over 13 mpg. On the return trip I got over 24 mpg running at 70 mph all day. I do have a tonneau cover for the bed which might help. I first took this new truck to Ohio in 2003 and only got 22 mpg with the same configuration. I did add a K and N air induction system before my last trip but this truck pulls like a champ without any additonal brains or Banks kits. The 5 speed transmssion is smooth and I know improvements have been made in the 09s.
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8.1L tons of gas power! - 2003 GMC Sierra 2500HD
By black dog - May 11 - 4:50 pmThe torque and power of the 8.1L is incredible, but be aware at the gas pump. An average of 9.1 mpg will be all youll get. Towing large campers or trailers is no trouble what-so- ever. Especially in lower range gears the 8.1L begs for more. All around I love the truck, including a great interior and stock stereo.
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Bad (good) Truck - 2003 GMC Sierra 2500HD
By shasta33 - May 26 - 10:00 amTruck is great. Needs better fuel economy and a bigger gas tank. Great power and transmition (8.1 / Allison).
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dura-maxed - 2003 GMC Sierra 2500HD
By workhorse - May 20 - 10:00 amI have owned my gmc for a short while and am very pleased with the Duramax/Allison combination,I have owned powerstrokes in the past,the difference is amazing, the Duramax power range extends for a much longer time, torque is great.Allison transmission holds gear going down steep grades and the mileage for a full size pickup is awesome (average is 18 mpg, I have gotten as high as 21 mpg)
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Good, bad, and ugly - 2003 GMC Sierra 2500HD
By Ted Sparling - January 5 - 5:50 pmThe Isuzu engine is the best part of this truck, along with the Allison tranny. The worst part has been all the GM stuff. Everything from numerous AC problems to leaks, memory features deleting themselves, multiple transfer case problems for auto 4WD, and leaking fuel injectors. If it were not for the dealerships attitude and incompetance i would buy again.
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Go GMC!! - 2003 GMC Sierra 2500HD
By GeorgeStrait - November 16 - 10:00 amGreat Power and Transmission, Had a Service 4WD Problem recently 5/2003 with 4000 miles on truck. Went into 4WD low w/o input from driver. Part not available, waited 3 weeks and a tow truck ride later!! YES I would buy another.
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What A Truck - Diesel/Allison Combo - 2003 GMC Sierra 2500HD
By Happy GMC Owner - April 5 - 10:00 amBought this last May, love the Duramax/Allison Combo - pulls my 10000 pound 5th wheel like it wasnt there. 12 MPG @ 65 MPH - nooo problem. Very stable on the road.
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Power Plus - 2003 GMC Sierra 2500HD
By jamminjay - February 28 - 10:00 am2003 Sierra with 8.1 liter 345 HP and Alison Auto. Plenty of power for towing. A little hestitant on take off when cold. 20,000 miles in 6 months and it runs like day 1. Fuel mileage is absolutely HORRENDOUS!!!! Towing an enclosed race car trailer x-country avg. mileage = 7.95. Driving enmpty no load at all avg. mileage = 12.98.
