I had a colleague riding with me the other day and indicated there was a vibration in the car. I thought he was crazy because I hadn't felt anything from the driver's seat. The car has 165,000 miles with an entire new rear suspension, bushings, control arms, shocks, axles, bearings plus guibo and driveshaft center bushing. (I bought the car at 130k only to have it stolen two weeks later and the SOB drove it like it was stolen and bent up the rear suspension so I fixed it properly....as a side note if anyone has State Farm for insurance I wouldn't place much faith in them honoring their side of the contract). Unfortunately my colleague, as mechanically disinclined as he is, was correct. There is a vibration that can be felt while riding in the rear seat. I'd hate to think it was the rear differential. Anyone with similar experience?