Lawn Mower Spindle with Pulley for John Deere 115 D110 E120 LA115 X126 Mandrel Assembly Replacement Part Number GY21098 GY20454 GY20867 GY20962 AUC15811 GY21099 Spindle Pulley GX20367 UC23728

What It Is

This is a replacement mandrel assembly with an integrated pulley for the cutting deck on select John Deere lawn tractors. It houses the spindle that drives the blade and includes the belt pulley, making it a direct swap for worn or damaged factory units.

Fitment & Compatibility

Check these before buying:

• Deck size: Fits 42-inch, 48-inch, and 54-inch Edge, Autoconnect, and standard stamped decks on models like the D110, D130, D140, D150, D155, D160, D170, E110, E120, E130, E140, E150, E160, E170, LA115, LA125, LA135, LA145, LA155, LA165, LA175, X126, X140, X145, X155, X158, X165, X175, X185, X190, and X195. Not for 54-inch 7-Iron or fabricated decks.
• OEM cross-references: Replaces John Deere GY21098, GY20454, GY20867, GY20962, AUC15811, GY21099, GX20367, and UC23728.
• Measurements: Spindle shaft diameter is 1 inch (25.4 mm); pulley outer diameter is 5 inches (127 mm) with a 3/4-inch-wide belt groove. Confirm your deck uses these dimensions.
• Quantity needed: Most decks use three spindles (left, center, right), but this part is sold individually. Buy the number you need.

Key Things to Know

• Build quality: Aftermarket unit with a steel housing and a sealed ball bearing. Some users report shorter bearing life than OEM, but it’s adequate for residential use.
• Installation: Straightforward bolt-on replacement—remove the deck, unbolt the old mandrel, transfer the blade and washer, and reinstall. Torque spindle bolts to 30–40 ft-lbs.
• Common gotcha: The pulley may have a slight wobble out of the box; check with a straightedge before installing. If excessive, return it.
• Belt fit: The pulley groove is slightly narrower than some OEM pulleys. If your belt is worn, replace it at the same time to avoid slipping.

Should You Buy It

If you have a compatible John Deere lawn tractor with a stamped deck and need a budget-friendly replacement for a worn or bent spindle, this is a solid choice for residential mowing. For heavy commercial use or if you want maximum bearing life, spend more on an OEM part.