I've noticed my engine rocks back and forth fairly easily when I rock the car back and forth or when I rev it up with the throttle lever on the back of the engine. I also feel a slight vibration occasionally at idle and it jumps a good bit when I shift out of park. That being said the motor mounts didn't look broken to me. Do the two motor mounts on the front just need to be tightened or do you think the rubber seal at the front of the motor mount has worn down allowing for all that travel? Lastly could someone tell me or show me where exactly the transmission mount is on the 3800? Is it very hard to change? Figure I probably should change it when I do the engine mounts. Then again maybe only the engine mounts to be fixed.

 

The trans mount is behind the drivers side wheel. It bolts to the side case of the trans and the side of the car. The lower engine mount is behind the passenger side wheel it bolts to the sub frame and bottom of the engine. Then the 2 upper dog bone mounts you are talking about. You can buy poly mounts to stiffen up the mounts and reduce movement but it will increase vibration a little.