Two problems related to transmission not go into gear have been reported for the 2009 GMC Acadia. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2009 GMC Acadia based on all problems reported for the 2009 Acadia.
Transmission wave plate issue. . . Car started "hard-shifting" from 2nd-3rd gear. . . Once this started, in a matter of a couple of days, had trouble even shifting into gear. . . Barely was able to drive it to dealership where they diagnosed the issue. . . My issue is that I have to pay $4500 for something that is a known dangerous problem with GMC Acadias across almost all model years based upon my research on the internet. This should be a recall situation. There is obviously a fault somewhere with the assembly process to be this huge of a problem. This could lead to a major accident. On 9/27, I was turning left off a main road into my subdivision. Car would not engage into gear, so was just coasting across the lane where oncoming traffic would be until it engaged maybe 3 to 4 seconds later. Had there been traffic coming, the oncoming vehicle would have slammed into me before I could have gotten across.
Initially noticed when shifting from park to another gear shifting was hard. About a week later noticed hesitation in shifting gears while driving at various rates of speed then the engine would rev once it shifted into gear. Eventually parked the car in drive then went to back out to take to dealership and it would not go into reverse. Vehicle towed to dealership where they replaced the wave plate and other parts that were contaminated. Since this incident the vehicle has not drove smoothly or shifted gears smoothly. It also gets less than 15 miles to the gallon during my daily commute now where prior to the transmission fix I would get 19-20. Vehicle hesitates and revs continually while driving and accelerating. When I returned the vehicle to the dealership stating there was still an issue I received "we could not replicate the issue" and sent on my way. After research on this site and other and reading the systemic issues others have had just like it I am concerned for my family and those around me safety if the transmission decides to stop while traveling high speed in traffic or when crossing traffic.