All depended on the owner some pulled the alternator at 50,000 miles for new bearings some would stretch it to 100,000 you had to replace the bearing with a 2 roll bearing, seals and the alternator drive on the engine
>My engine only has 55,000 miles on it, so my hope will lie in the alternator lasting for a while longer.This is a good resolution because most parts give signals of pending problems. The 50DN is pretty big and hard to imagine it blows up and stop working, most likely make noise or lose o less output.
Richard,Do a bit of reading of the maintenance manual and it clearly suggests alternators should last for quite awhile. The 8v71 manual calls for looking it over a 100k interval, so you should be fine.