i just had my acadia slt1 for about 550 miles now and very happy over all but my question is that if you guys also experience this little knock under on initial drive? everytime you start and reverse and go to drive and go you will hear and feel a little knock down but it doeasnt do that on stop and go only on initial drive . i was thinking probaly transmission thing or what please let me know ,thanks everyone. but overall the car is great i was concern with the gas mileage at first but i think i will get 18 city and 22 highway . good day everyone!