cub cadet 1415 help
 

i have a cub cadet 1415 im fixing for a friend....it stutters while in 3rd gear....goes fine in all the other gears. 3rd it seemed like it was missing teeth on the gear. i took the transmission apart, and found no metal pieces, shavings. all the gears look intact, all the spines the gears slide onto on the shaft look fine and intact....any idea as to why it would skip? someone else out there must have had a problem similar to this one.