2 Pack GY21098 Spindle Assembly with GX20367 Spindle Pulley GY20629 and GY22172 Idler Pulley GX20072 Belt 1/2x103 for John Deere D100 D105 D110 D120 D125 D130 LA105 Lawn Tractors

What It Is

This is a comprehensive replacement set for the cutting deck drive system on select John Deere lawn tractors. The kit includes two spindle assemblies (with pulleys), an idler pulley, and a 1/2-inch by 103-inch belt—everything needed to refresh the deck’s blade drive and tensioning system.

Fitment & Compatibility

Before buying, verify your tractor model and deck size. This kit fits John Deere D100, D105, D110, D120, D125, D130, and LA105 models, but only with 42-inch or 48-inch decks (check your deck’s stamped model number). The OEM spindle part is GY21098, pulley GX20367, idler GY20629 or GY22172, and belt GX20072 (1/2x103). Measure your existing belt length and pulley diameters to confirm match. Aftermarket set replaces multiple OEM parts—no guarantee it fits non-Deere decks.

Key Things to Know

• Quality vs. OEM: Aftermarket spindles may use lighter bearings or thinner steel. Expect 2-3 seasons of residential use; OEM lasts longer under heavy cutting.
• Installation difficulty: Moderate. You’ll need a jack, socket set, and torque wrench (spindle bolts ~35-40 ft-lbs). Belt routing is critical—check a diagram for your deck.
• Common gotcha: The idler pulley’s bolt size may differ from OEM (often 5/16″ vs. 3/8″). Have a metric and SAE set handy.
• Belt length: 103″ is exact for 42″ decks; 48″ decks use a longer belt (check spec). Measure old belt before cutting.

Should You Buy It

If you have one of the listed John Deere tractors with a 42″ deck and need to replace worn spindles and belt at once, this kit is a cost-effective, time-saving option. For heavy commercial use or if you prefer OEM longevity, buy genuine John Deere parts individually.