On the 300F I owned for 23 years and now on the 1963 300 Touring 8, I have replaced both front and rear U joints with modern Spicer units. Any good driveshaft shop can do this and do it quickly. Any time you are touring, and if something goes wrong, most gas station mechanics can get you moving again . On both the cars above, the rubber covering split, then the rib got bigger which set up a racket for 30 miles until it finally broke off and the noise went away. Just remove the drive shaft and take it to the shop. Tell em Lefty sent ya...