17012-0101831

Remove the transmission assembly from the vehicle and disassemble the main shaft or countershaft where the 17012-0101831 gear is located.

Use high-quality GL-4 or GL-5 gear oil. Contaminated oil acts as an abrasive, wearing down the gear teeth. 17012-0101831

Drain the transmission fluid completely before opening the housing. Remove the transmission assembly from the vehicle and

Check the surrounding synchronizer hubs and bearings for wear. Replacing a gear without checking its counterparts often leads to premature failure. 17012-0101831

Listen for high-pitched whining (indicates wear) or "clunking" sounds (indicates chipped or broken teeth). If the truck pops out of gear under load, the engagement teeth on this part may be worn.