GX21381, 80-91-063 Spindle Pulley Fit for John Deere 42" Deck S240, Fit for John Deere 54" Deck 190C, D170, G110, LA150, LA175, E180-3 Pack

What It Is

The GX21381 (80-91-063) spindle pulley is a replacement part for the blade drive system on select John Deere lawn tractors. It transfers belt power to spin the mower blades, sold here as a 3-pack for 42" and 54" cutting decks.

Fitment & Compatibility

Before buying, verify your deck model and spindle measurements. This 3-pack fits John Deere 42" decks (model S240) and 54" decks (models 190C, D170, G110, LA150, LA175, E180). Original OEM part numbers include AM137333 and AM141107. Measure your old spindle pulley: this replacement has a 3.5" diameter, a 5/8" bore, and a 1" overall height. Confirm your deck uses a standard 5/8" shaft—some newer decks may differ. Not compatible with zero-turn mowers or decks outside the listed models.

Key Things to Know

• Quality vs OEM: Aftermarket part at a lower price than John Deere OEM. Reported as durable for homeowner use but may wear faster under heavy commercial conditions.
• Installation: Moderate difficulty. Requires removing the deck, belt, and blade; then unbolting the old spindle and reassembling. Basic hand tools and a torque wrench recommended (tighten to 20-25 ft-lbs).
• Common gotchas: Check that the pulley’s keyway aligns with your shaft’s key (if applicable). Also inspect bearings in the old spindle housing—if they’re worn, the pulley alone won’t fix vibration.
• 3-pack value: Cost-effective if you need to replace multiple spindles, but only buy if all three are needed; single failures are more common.

Should You Buy It

This 3-pack is a solid buy for homeowners with a listed John Deere model (42" or 54" deck) who want to replace multiple worn spindles at once for a lower cost than OEM. Skip it if you need only one pulley, have a non-listed deck, or require commercial-grade longevity.