AM136328 Mower Deck Gage Wheel Arm 3/4" Dia. LH Front or RH Rear for John Deere X300 & X500 Series with 48 in & 54in Mower Deck, fits X300, X304, X310, X320, X500, X530, X534, X540 etc

What It Is

This is a replacement gauge wheel arm (AM136328) for John Deere X300 and X500 series lawn tractors equipped with 48-inch or 54-inch mower decks. It supports the front or rear of the deck to prevent scalping and maintain consistent cutting height.

Fitment & Compatibility

• Deck size: Fits only 48-inch (48C, 48S) and 54-inch (54C, 54S) mower decks. Does not fit 42-inch or 60-inch decks.
• Position: Left-hand front or right-hand rear (LH Front / RH Rear). The arm is specific to these two corners—not interchangeable with the opposite sides.
• Models: Compatible with X300, X304, X310, X320, X500, X530, X534, X540, and similar X300/X500 series tractors. Verify your model number on the tractor frame tag.
• OEM vs aftermarket: This is a direct OEM-style replacement for John Deere part AM136328. Aftermarket versions may vary in metal thickness or bushing quality.
• Measurements: The arm has a 3/4-inch diameter pivot pin hole. Confirm your existing arm’s pivot point size matches.
• Check before buying: Look for cracks or wear at the pivot hole and the wheel mounting slot. Ensure the wheel (sold separately if needed) uses a 3/4-inch axle.

Key Things to Know

• Quality: Most users report solid build with heavy-gauge steel, but some note the paint finish chips easily. Inspect for burrs on the pivot pin hole before installation.
• Installation difficulty: Easy—requires removing one bolt and washer per arm. No special tools needed. Expect 10–15 minutes per side.
• Common gotcha: The arm is directional. Installing on the wrong side will cause the wheel to sit at an angle and wear unevenly. Mark left/rear before removal.
• Bushing wear: If the pivot hole is elongated on your old arm, replace the pivot pin bushing (Deere part M155232) at the same time to prevent slop.

Should You Buy It

If your deck is scalping or the gauge wheel arm is bent, cracked, or has a worn pivot hole, this is a straightforward, cost-effective fix. It’s ideal for DIY owners with a 48-inch or 54-inch X300/X500 series mower who want to restore proper deck float and cut quality without buying a whole wheel assembly. Avoid if your deck is a different size or you need the opposite side arm.