91 Bronco "clunk" mystery solved.
 

For years, I have had a "clunk" occur when accelerating from a full stop. Repeated inspections of the u joints did not indicate any problems. The problem was significantly more noticeable in hot weather. Recently, following the onset of cold weather, a loud repetitious squeak developed that occurred in unison with drive shaft rotation. Due to the annoying sound, the drive shaft was removed and examined. The Cardan Joint was found to be extremely stiff and non-flexible due to the wear of it's internal components. Following it's complete rebuild, all noises and clunks were eliminated.

Thanks for the info. Have a Happy Holiday !

Good info.

how do you rebuild the joint?