I'm on my way home from work today and after some stop and go driving because of a broken down semi on Harlem, I get past the congestion and start accelerating up to around 55. Just gentle acceleration, not even half throttle. As I go past 40, I feel a strong rumble that seems to be coming from the back of the car. I turned onto side streets and had no problems driving under 30 mph. Stopped and looked at all 4 wheels but didn't see anything wrong. Looked under the car but no errant fluids or obvious damage. Started for home again driving slowly and testing the car. When I would get up to around 35, the rumble would start again. Motor seems fine. Trans seems fine. Doesn't matter which gear I'm in. I may have felt a little side to side shimmy but it could be my imagination. I'm guessing wheel bearing? Could a bad bearing make the car rumble? Anyone had something similar happen to them or know what it could be?