The MTD 9180139B Spindle Assembly is a genuine OEM replacement part designed for various MTD, Cub Cadet, Troy-Bilt, and other brand lawn tractors and riding mowers, commonly used on 42-inch and 46-inch cutting decks. This complete assembly includes the blade shaft, housing, bearings, and a grease fitting, providing a direct fit for maintaining efficient blade rotation and cutting performance. It features a 3-bolt mounting pattern and a 6-point star blade mount for secure attachment. Replace worn or damaged spindles to restore smooth operation and extend the life of your mower deck.