The piece shown in the picture is not the gaiter. It is a seal that protects the centering ball in the double cardan joint in the prop shaft. The gaiter, as jafir pointed out, is a rubber bellows type thing that provides some protection at the prop shaft slip-joint.

 

ah, thx for the clarification!

 

Local Part store sell them.

 

As far as replacing the seal that protects the centering ball. Yes, it's a royal PIA. Might as well rebuild the entire shaft w/ new greaseable u/joints.