I just acquired a '09 Cobalt Ecotech, Auto, 47,000mi. from my aunt that cannot drive anymore due to illness. The car has been meticulously maintained since new. It has a strange vibration from the driveline?? It sounds just like a wheel bearing. There is no telling how long this noise has been going on due to the fact that my aunt is 70% deaf on a good day. Here's what I've done so far..... Jacked up the left side, Started and ran the car in gear. There was no noise whatsoever. Then I jacked up the right side, Started and ran the car and the noise was present. I changed the right wheel bearing and it still has the noise. Now for the mysterious part. Upon further examination I noticed the noise is NOT present when the car is put in 1st gear or reverse?? however when shifted into 2 or above the noise instantly kicks in??? Does this sound like a bad transaxle?