At Jacks Transmissions, we have a lot of V160 rebuilds under our belt. Due to this, we have found it to be very common to replace gears which have been damaged due to synchro grinding.
The engagement teeth on the gear can be rounded off, chipped or worn down if a synchro sleeve has been crashing into the gear. When you feel a synchro grind while you shift, what you are doing is crashing the synchro sleeve into the gear engagement teeth. The more you grind the gear, the more it will damage the engagement teeth and then will have to be replaced.
Our rebuilds include replacement gears. 2-3 depending on the Stage build you choose. These builds are not set in stone and if you have more gears which are damaged, or fewer, the build can be modified for that change. The gears we include have been our experience to be the most common requiring replacement. 90% of the time, the gears included in the build you select are needed and have to be replaced to assure a smooth and accurate shift.
Picture below on the LEFT is of a gear with damaged engagement teeth. Nice sharp new teeth on the RIGHT. The gear with the damaged teeth will cause an unpleasant shift: