[Metroporter]

I just replaced the drive-shaft on my 1997 328i automatic. The new drive-shaft came fully assembled & balanced. It also included a new center bearing support & nose bushing. Aside from a new flex-disc / guibo, it was a simple bolt-on procedure. I got everything put back together and drove it for a couple days with no problems - in fact I can't remember the last time it drove that smoothly.

I then took it to a local tire shop for a rotation & balance of the tires. As I drove home, I noticed a slight vibration as the car passed through ~50mph. Otherwise, no problems. On a second drive, later that day, the vibration was a bit worse. Third errand: it was out of control. I coasted down from 65mph and eased on the brakes as I hit the exit ramp and I honestly thought I was going to lose control of the vehicle. I immediately released the brakes and the vibration only subsided with a reduction in speed

A) The first thing I thought of was the lug nuts - they were all tight. B) I've now removed the wheels and checked all of the suspension components - everything there seems to be in good repair. C) I dropped the exhaust (with heat shield) for an inspection of my drive-shaft work - all appears to be in good order from the flex-disc, all the bolts are tight, the center bearing is tight, the balancing-welds on the drive-shaft are all in place... I am at a loss! Any suggestions would be greatly appreciated!