I had a dodge 2500 CTD with a carrier bearing in the back giving me 3 Ujoints, every year I had to replace all 3, I always went to the greaseable Ujoints and lubed then once a month, after about the 9th month 1 by 1 they would stop taking grease and about 3 months after that they ceized up and fall apart. I used the truck as a daily driver and only hauled stuff about twice a year. A guy at Napa told me to try a non greasable joint and so I replaced only 1 of the 3 with a non greaseable Ujoint and the other 2 greaseable, about a year later the 2 greaseable failed and the nongreaseable was still tight and smooth, I replaced the failled Ujoints with nongreaseable and never had another trouble. The nongreasable Ujoints I purchased weren't even the highest quality ones, They were the middle of the road ones. I do live in pennsylvania where we put road salt thicker than than the fallen snow, so maybe this has something to do with my results also. Well take what you want from this info! I also have a similair story about ball joints!