Its my understanding that the reason the nut works loose and causes failure is from lugging the engine loaded and unloaded. Exactly what those RPM #'s are I don't know. Maybe some one can fill the forum in. I know if mine fails once warranty is has expired,and requires more than the nut,that truck gets a new home I'll trde it in to another dealer.
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97 Ram 2500 4x4 Driftwood 5spd 3:54 E-brake Isspro,boost&pyro guages 24,500 miles