bought brand new in 2004. at 45,000 miles the gauge cluster went, @ 88,000 miles the catalytic converter went, @ 7 years old the cab corners and rocker panels started to bubble despite always washing and hand waxing, along with car washes. At 110k I was using coolant and heard my lifters ticking. With no warranty I pulled the valve covers only to find anti-freeze and my cylinder heads covered in muck!!! The warped cylinder heads that caused the disaster were on millions of gm vehicles between 2002 and 2006. Cadillac's, yukons, sierras, etc, A local mechanic with gm explained that they knew about the problem but continued to use the heads because they had purchased millions of dollars worth of them and knew the buyers would get 100k miles out of them. He explained a recall would have cost millions of dollars so they decided it was pretty much just cheaper to screw the buyer. 3k in parts and labor and the car was down for a week. Needed all new lifters and heads planed. @ 120k rust is through the cab corners and rocker panels. Won't pass inspection in NH, Large holes. Now at 146k It's using coolant again. I tasted the water dripping from the exhaust pipe. Sure enough, anti-freeze. Time to go. Bad luck with 3rd gmc in a row. I'm a bow tie guy with chevelles and other muscle but a ford 250 super duty is looking pretty good. Gas of course where as nothing beats a Dmax.
Bought this truck used at 126k miles drove for a month started loosing coolant took it into my dealership they found out it was the water pump not the heads replaced for free I've had to do shocks ball joints tire rod ends maf sensor left bank exhaust manifold gasket evap control module u joint and axle shaft seals because I'm super picky but understand that I did not buy a brand new truck I bought used this truck pulls like a dream rides great just wish it didn't govern at 98 and had better stopping power I drove an 08 and decided I still liked the 04 better plenty of power and mpg isn't bad 04 sierra sle 5.3 extended cab 4x4 z71 is a keeper for sure out Mudd's my buddies fords and dodges
I drove this truck across the country, no problems and i had a trailer in pull. Maine to Washington. Very comfy and with a few add ons, the gas mileage for me is low 20's high way. 5.3L. Good truck, Recommend.