This genuine MTD replacement part is a worm gear for use with tillers. This worm gear has 30 teeth. A properly functioning worm gear is essential for the safe and reliable use of a tiller. The worm gear attaches on the inside of the gear case, and drives the shaft to turn the wheels of the tiller. The worm gear may become worn out or damaged with extended use, necessitating replacement. Remember to check the tiller periodically to spot any wear or damage. This part is an identical replacement for a worm gear that is missing, worn out, or damaged. Prior to working with this part, please refer to the original product manual for installation instructions. Additional tools may be required for installation of this part. For safety, always wear gloves and ensure unit is powered down prior to performing any installation or repair.This high quality OEM replacement part is sourced directly from the manufacturer, and it is sold individually. It is made of high-quality durable metal. This part is compatible with Troy-Bilt and more tillers. Please note: original part numbers 2398136, GW-2654 are now obsolete, and manufacturer has replaced the original part numbers with this part.