918-06978 618-06978 Spindle Assembly Fit for Cub Cadet/MTD/Troy Bilt 54 Inch Mower Deck ZT1-54 ZT2-54 RZT-L54 RZT-S54 XT1-ST54 XT1-GT54 XT2-GX54 TB2454, Fit for Craftsman T8400 G8400 Z6660 2 Pack

What It Is

This is a 2-pack of spindle assemblies designed for 54-inch mower decks on Cub Cadet, MTD, Troy Bilt, and Craftsman zero-turn and lawn tractors. It replaces the OEM part numbers 918-06978 and 618-06978, which support the blade rotation on the deck.

Fitment & Compatibility

Before buying, verify your deck is exactly 54 inches (not 50 or 60). This fits Cub Cadet ZT1-54, ZT2-54, RZT-L54, RZT-S54, XT1-ST54, XT1-GT54, XT2-GX54, and TB2454 models. Also fits Craftsman T8400, G8400, and Z6660 with 54-inch decks. Measure the spindle housing height (approx. 3.5 inches) and shaft diameter (0.625 inch) to confirm match with your old unit. It’s an aftermarket replacement, not OEM Cub Cadet, so check that the bolt pattern (4-hole, 3-inch spacing) aligns with your deck.

Key Things to Know

• Quality: Most users report it’s a solid aftermarket alternative to OEM, but some note bearings may not last as long as factory parts (expect 1-2 seasons under heavy use).
• Installation: Moderate difficulty—requires removing the deck, unbolting the old spindle, and transferring the pulley and blade. Have a torque wrench handy (blade bolt typically 70-80 ft-lbs).
• Common Gotcha: The spindle may come pre-greased, but check—if dry, add grease before mounting. Also verify the shaft keyway aligns with your pulley.
• Compatibility: Double-check your deck’s spindle count (3 spindles on most 54-inch decks) and that this replaces the center or outer spindles (identical in this kit).

Should You Buy It

If you need a budget-friendly, functional replacement for a worn or damaged spindle on a 54-inch Cub Cadet, MTD, Troy Bilt, or Craftsman deck, this 2-pack is a solid value. It’s best for DIYers comfortable with medium-level mechanical work and who don’t require OEM longevity. For commercial or heavy daily use, consider OEM spindles for longer life.