Idler Pulley (AM135526) Fits J OHN Deere Ztrak Z355E Z245 X310 Z425 X324 X330 X350 Z435 Z445 Lawn Mower Riding Mower & Zero Turn Tractor

What It Is

The AM135526 idler pulley is a replacement part that guides and tensions the mower deck belt on select John Deere ZTrak zero-turn mowers and X-Series lawn tractors. It keeps the belt tracking properly to prevent slipping or throwing during cutting.

Fitment & Compatibility

Before buying, confirm your machine model and deck size. This pulley fits John Deere Z355E, Z245, Z425, Z435, Z445 (ZTrak) and X310, X324, X330, X350 (X-Series) tractors, typically with 48- to 54-inch decks. Check your original pulley’s outside diameter (usually 4.0 inches) and bearing width (0.75 inch). AM135526 is an OEM-equivalent aftermarket part—measure your existing pulley’s bolt hole pattern (two holes, ~3.0 inches center-to-center) to ensure match. Verify your deck belt routing diagram; a mismatched pulley can cause belt slip or premature wear.

Key Things to Know

• Quality: Aftermarket pulleys vary—this one has sealed bearings and a steel hub, but may not match OEM durability. Inspect for wobble before installing; a cheap bearing can fail in one season.
• Installation Difficulty: Easy to moderate. You’ll need a socket wrench (usually 1/2-inch or 5/8-inch) and possibly a breaker bar for rusted bolts. No special tools required, but access can be tight under the deck.
• Common Gotchas: Loose or missing spacers/washers from the original pulley can cause belt misalignment. Keep all hardware. Also, check the belt for wear—a new pulley on a worn belt can still cause slippage.
• Fitment Nuance: Some X-Series models (e.g., X330) use a different pulley on the spindle vs. the tensioner arm. Verify you’re replacing the correct idler, not the spindle pulley.

Should You Buy It

If you need a budget-friendly replacement for a worn or noisy idler pulley on a compatible John Deere lawn tractor or ZTrak, this is a solid option. It’s not for heavy commercial use—expect 1-2 seasons of residential mowing. Skip it if you demand OEM longevity; otherwise, it’s a good value for DIY repairs.