Over 200K
I had my factory original rear drive shaft rebuild/balanced at 210K. Ujoints had to be shot... Right!
Truck pulled lots of trailers, ran through four sets of rubber and one 5sp transmission. Joints never touched. Ever!
Driveline shop saved the worst joint. They said it had little if any wear and it was only because it was dry others like new! Nothing was loose or out of balance.
They put in all new spicer joints with zerks. Strongly recomneded that I grease every oil service and I do.
I read a comment a while back that the "Mitchells'" found the factory zerkless joints to be the strongest. After seeing how many miles a zerkless joint can go, and how much of a mess I now have on the onderside from the surplus grease, I wish I would have put the factory originals back in or at lease the spicer ones without zerks.
jjw
ND