Rbell003
New member
- Joined
- Feb 26, 2013
- Posts
- 2
The vehicle is a 2005 GMC Sierra 2500HD with the 8.1 Vortec engine. It has 50,700 miles on it. The truck used to sit in the carport most of the time just recently my son been driving it every day for about two months now. It's starting to have shifting issues with a P0700 code. Thought it was the NSBU switch, replaced it cleared the code and problem still exists. My son described the truck as going into a limp mode so I took it for a test drive. It will up shift from first to third but when I stop and accelerate it gets stuck in first gear with a P0776 and P0732 code. If I stop and turn the ignition off and back on and start to accelerate in tow mode it will up shift from first to third again. About four different times that I would stop and turn the ignition off and back on it had shifted through all the gears. But most of the test drives it gets stuck in first until I stop turn the ignition off and back on. So not really in a limp mode which is only third and reverse. I'm guessing it's one of the solenoids going bad or a sticky valve. I was told letting the truck sit too long was not a good thing. Has anybody else experience these symptoms and tell me where to start.
