Hi JU the propshaft that has dropped is it above the metal guard? if ti is two bearings are mounted in rubber that inturn bolt through this plate. When these rubbers get old they crack and the rubber bonding comes off the foot holding the captive bolt that passes through the tin guard. If you can move the prop side to side up and down in the area of the guard then that is what has failed I'v had it happen to me
No probs if you can get the car up in the air it will be easy to spot be careful if you have to remove the bearings and rubber mounts the bolts that go through the metal plate will rip out of the rubber for fun. Heat will knacker the rubber up WD and a lot of luck is what you need, you will need to split the prop to change the bearing don't forget to mark the prop so it goes back as you have taken it apart.