Lawn Mower Tractor PTO Clutch Cub Cadet MTD Troy-Bilt White 717-05121 917-05121

One clutch serves machines sold under Cub Cadet, MTD, Troy-Bilt, White Outdoor, Bolens, and Huskee badges - all built on the shared MTD platform with the 05121 clutch path. For the repair shop that sees a Cub Cadet one day, a Troy-Bilt the next, and a White Outdoor the day after, one SKU covers all of them - same chassis family, same clutch, different paint. For dealers, one part number replaces the cross-referencing of six brands at the counter.

The 05121 family serves the 42-inch deck class of the MTD zero-turn line - the RZT-L42, RZT-S42, ZT42, ZT-L42, Z6000, and the Mustang 42 XP - with documented model-year fitment for the 2013 and 2014 production. The clutch geometry is calibrated to the 42-inch fabricated deck drive: correct bore, correct pulley, correct belt path. For owners and shops, one SKU covers the 42-inch family without cross-referencing between model-specific part numbers.

Rated at 80 ft-lbs, this clutch is intentionally calibrated to the 42-inch entry-zero-turn duty cycle - the engagement authority these machines need for reliable blade spin-up, without the excess current draw of a heavier clutch that would strain the 20–24 HP charging system. The rating delivers crisp blade engagement through routine residential mowing and mulching, and supports the frequent stop-start cycling of zero-turn operation around landscaping obstacles.

One clutch replaces 717-05121, 717-05121A, and 917-05121, cross-references the Stens 255-062X, and covers the Bolens, Cub Cadet, MTD, and White Outdoor numbers on the same path. Whether the failed clutch carries the 717-05121A or the 917-05121 reference, one part covers it - no cross-referencing traps, no risk of ordering a clutch that matches one superseded number but not the current machine revision.