A scored, nicked or gouged driven gear is usually indicative of a damaged
drive gear on those vehicles that have the drive gear integral with the
transmission output shaft. Carefully inspect the output shaft for imperfections
and replace if necessary.
A driven gear with two or three adjoining teeth badly scored is indicative
of improper assembly procedure. The gear should be inserted in the transmission
while simultaneously turning the driveshaft. This will ensure initial gear
engagement and prevent gear damage. Never use force.
Whenever a drive gear is replaced, a new driven gear should also be
installed, regardless of its apparent condition.