So i put a valair dd 3600 slipper clutch in my 03 cummins and i have almost 20,000 miles on it and it gave up on me in traffic and the clutch quit clutching. Pulled clutch out of truck clutch was worn out and looking kinda sad i never pulled with the truck and the most towing i have done with it was to pull a boat to the lake and a car across the state ....just wondering if this is a normal problem or if i just got a junk clutch from the start