It happened to me..
Last week I had a loud bang under the shifter while driving. I thought I ran over something. At the next light i noticed that when I hit the gas the car shook until I let off or until i got into 3rd gear. After a nervous drive home I found a had broken 1 of the 3 bolts that connects the drive shaft from the trans to the flex disk. Found 1/2 of the bolt stuck into the body above the disk. Replaced the bolt and all is well.