TCINDRR AM138220 AM136329 Mower Deck Gauge Wheel Arm Compatible with JD X300 X304 X310 X320 X324 X340 X500 Series

What It Is

This is a replacement gauge wheel arm for John Deere X300 and X500 series lawn tractors. It mounts the front gauge wheels that keep the mower deck level and prevent scalping on uneven terrain.

Fitment & Compatibility

Direct fit for: John Deere X300, X304, X310, X320, X324, X340, X500, X520, X530, X534, X540, X560, X570, X580, X590 (all with 42- to 62-inch mower decks that use the AM138220 or AM136329 arm).

OEM cross-reference: Replaces John Deere parts AM138220 and AM136329.

What to check before buying:

• Measure your existing arm length (center of pivot hole to center of wheel axle hole) – this arm is roughly 8.5 inches.
• Verify your deck uses a single-arm design (not a dual-arm or bracket-style system).
• Confirm your wheel spindle diameter matches the arm’s spindle hole (typically 5/8 inch).

Note: This is an aftermarket part, not OEM John Deere. Some users report slight dimensional differences that may require minor adjustment or filing.

Key Things to Know

• Low rating (2.4/5) suggests quality control issues – multiple reviews mention premature wear, bending, or weld failure within one season.
• Installation is straightforward – unbolt the old arm, bolt on the new one. No special tools required, but you may need a jack to lift the deck.
• Check for metal thickness – OEM arms are thicker steel; this aftermarket arm may be lighter gauge, which can bend under heavy use or on rough terrain.
• Warranty is limited – most sellers offer 30-day returns, but long-term durability is unproven.

Should You Buy It

Buy this only if you need a cheap temporary fix and can tolerate replacing it again within a year. The low price is tempting, but the poor ratings and reported failures make it a poor investment for regular mowing. Spend the extra $20–30 for an OEM John Deere arm (AM138220 or AM136329) if you want reliability.