If what you're hearing is a ratcheting like sound, it very well could be the bearings inside the rzeppa joint going bad. Have you looked at your gas tank skid plate or bottom of your tub near the joint area to see if there's any grease flung on it? If there is, the CV boot has failed and the bearings going bad are in fact what you're hearing. You should be able to find a factory rear take off shaft for about $250 or less. A lot of times, you can find one for FREE. If it were me, this is what I would do until I could save up enough to get a proper u-joint style double cardan shaft with adjustable upper control arms to set your pinion angle. In the end, the factory shaft will still be weak in the tube and finding replacement parts in a pinch is near impossible. You can find new 1350 u-joints just about anywhere and can shaft rebuilt just about anywhere as well. You cannot do this with a factory shaft.
