I have never seen or felt anything like this. I was driving my 1970 144 yesterday when I noticed some strange noises coming from the front end of the car (like metal "clicks", something was braking loose), then as I slowed down there was a terrible vibration (I felt it in the engine, the steering wheel, even the hood was shaking, but the engine didn't stall. As soon as I stopped the engine was running smooth and fine, no unusual vibration or noise. I started to drive again and it happened again, really bad at about 10mph then got a little better at faster speeds. I drove the car at about 45 mph and it felt like something was "rubbing", like the transmission (automatic) or driveshaft was coming apart, along with weird groaning noises especially during accelleration. I then tried shutting off the engine and coasting to a stop and the vibration was still there! I drove the car home and parked it. I have looked at everything and can't see anything wrong. My gut feeling is that it's one of the following, but I'm not sure:

1. A motor or trans mount broke
2. Something with the driveshaft is bent or has come loose
3. Something with the auto transmission (even though it's shifting fine!)

Any ideas what this could be?