Two problems related to power train have been reported for the 2005 GMC Sierra. The most recently reported issues are listed below.
Issues with emissions switch. Check engine light will not go off. Also 3 and 4th gear are completely gone out. I do not tow or have had anything even remotely heavy in this truck. It's a 2005 GMC Sierra with only 78,480 miles on it. I am not the only one having issues with this 4 speed transmission. It is not heavy duty enough for this size truck. Gm needs to recall all of these transmissions. When it first started slipping I lost all power going down the road at about 55mph. The vehicle that was behind me slammed on his brakes to avoid hitting me. This problem with the transmission is going to kill someone.
I own a 2003 2500 hd 4x4, a wonderful vehicle it would be even more wonderful if I could find a dealer that would stand behind his product. My next car probably will not be GMC or chevy. I have owned the car since June of 2003. Due to the nature of my business I already have 98,000 miles. During that time I have complained about fuel mileage. The reports lie. Nobody will do anything about the fuel mileage. Because it can't get any better because they lied. I have lost a vaccume pump, and a left front wheel hub which had to be completely replaced. What prompted my complaint is that I have started developing a vibration at 77-83 mph. Dealer rep says you shouldn't be doing 80 mph. Therefore since our mechanics can't speed in your vehicle ( completely understandable) you don't have a vibration. Despite the fact that the vibration occours at 80mph I still have a vibration and just because it is against the law, ( 75 is about the norm on our highways), doesn't mean I don't have a vibration. My guess is that it is either another wheel hub, or something in the installation of the new vaccume pump. Because after they replaced that it ran good for awhile. The vibration is getting worse and I am at 97-98,000 miles. Vehicle is also starting to surge, but not all the time. From what I have read about the other complaints it could be the ac acting up. But since it wasn't surging this time, well if your a consumer reading this you know the story. I have told you all the bad. Now for some good. . . . The brake system on this car is beautiful I am still less than half all the way around. The brake system is perfectly tuned from front to back. I have hauled cars and trailors from time to time and the engine transmission and brakes all work together beautifully. Its the service I am complaining about.