The most common cause of that damage to a carrier is a badly worn or destroyed front pinion bearing. When the driver lets off the throttle, the pinion gear gets sucked back against the carrier. I've also seen a loose pinion nut cause the same sort of problem.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!