Two problems related to transmission not engage have been reported for the 2008 GMC Acadia. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2008 GMC Acadia based on all problems reported for the 2008 Acadia.
While driving the transmission did not engage into the next gear and the engine rpm's went very high for a short time and the transmission finally engaged the next gear very roughly. I immediately stopped an placed the vehicle in park. I then placed the vehicle in drive and began to accelerate when the vehicle missed the same gear again. I stopped the vehicle and placed I took the vehicle to a local mechanic who stated that the transmission would have to be rebuilt or replaced. He informed me that this is a major issue with this vehicle and that I should research it on the internet where you can find thousands of the same issue from owners of the same vehicle. The problem that GMC is aware of is a defective wave plate in the transmission that fails, causing the issue. This should be recognized as a defect and GMC should be held accountable.
We are a family of 5 driving along the highway when the check engine light came on. We stopped and put the car into park. When I went to put into drive, the car would not engage. Finally after a few minutes we were able to get the car going again, but the car would not shift itself (automatic transmission). We then had to drive along the side of the highway for 13 miles to the next town with the hazards on at 20 miles per hour. Went to a chevy dealership and after they read the codes, there appears that the transmission is completely out. We were more than 800 miles away from home on vacation in missouri. The car is still in missouri at the dealership, as they will not be able to take the transmission apart until early next week.