AM143737 / AM136693 Idler Pulley for John Deere Z425 Z435 Z445
AM143737 / AM136693 Idler Pulley for John Deere Z425 Z435 Z445
Overview
This aftermarket AM143737 mower deck idler pulley replaces John Deere AM136693 on select John Deere lawn tractors and EZtrak or ZTrak zero-turn mower decks.
This flat idler pulley helps guide the mower deck belt and maintain proper belt alignment through the deck-drive system. Common applications include select John Deere Z425, Z435, and Z445 mowers equipped with compatible 48-inch or 54-inch decks.
Do not order by mower model, deck width, or pulley appearance alone. John Deere decks can use multiple pulley sizes and positions within the same belt-routing system.
Key Features
- Aftermarket mower deck drive idler pulley
- Primary Replacement Number: AM143737
- Replaces Earlier John Deere Number: AM136693
- Pulley Type: flat mower deck idler pulley
- Outside Flange Diameter: approximately 5.92 inches – 150.4 mm
- Center Bore: approximately 0.66 inch – 16.7 mm
- Overall Width: approximately 1.04 inches – 26.47 mm
- Effective Diameter: approximately 5 inches – 127 mm
- Belt-Contact Width: approximately 0.75 inch – 19 mm
- Complete replacement pulley assembly with center bearing
Measurement note: The outside flange diameter is larger than the effective belt-contact diameter. Match the AM143737 or AM136693 part number first rather than comparing only one published pulley measurement.
Compatible John Deere Models & Deck Paths
This idler pulley fits select mower deck configurations within the following John Deere model paths:
- John Deere LT190
- John Deere Z225
- John Deere Z235
- John Deere Z245
- John Deere Z255
- John Deere Z355E: select early-production applications
- John Deere Z425: select 48-inch and 54-inch mower decks
- John Deere Z435: select 48-inch and 54-inch mower decks
- John Deere Z445: select 48-inch and 54-inch mower decks
Fitment note: Not every deck configuration within these model families uses AM143737. Confirm the mower model, serial or PIN range, deck size, and AM143737 pulley callout in the model-specific parts diagram.
Replaces OEM Part Numbers
- John Deere AM143737
- John Deere AM136693
Important Fitment Check
Match the original pulley number before ordering. This replacement is intended for mower deck positions calling for John Deere AM143737 or AM136693.
Do not treat AM143737, AM128118, and AM135526 as interchangeable. These are separate pulley paths that can have different diameters, widths, offsets, and deck positions.
Customers whose original pulley or OEM diagram calls for AM128118 should use the dedicated AM128118 deck pulley replacement.
Before Ordering
- Confirm the original pulley or parts diagram calls for AM143737 or AM136693
- Verify the mower model, serial or PIN number, and deck size
- Confirm the pulley position in the deck-belt routing diagram
- Compare the center bore, pulley width, and outside diameter
- Inspect the mounting bolt, spacer, washer, and idler arm
- Check the deck belt, tension spring, spindle pulleys, and other idlers for wear
Common Symptoms of a Worn Idler Pulley
- Grinding, squealing, rattling, or chirping from the mower deck
- Deck belt repeatedly coming off the pulleys
- Visible pulley wobble or looseness at the bearing
- Pulley that does not rotate smoothly by hand
- Uneven wear, fraying, or glazing along the deck belt
- Excessive heat around the pulley bearing
- Reduced blade speed caused by poor belt tracking
A worn belt, weak tension spring, bent idler arm, seized spindle, or damaged mounting hardware can quickly damage a replacement pulley. Inspect the complete deck-drive system before installation.
What’s Included
- 1 aftermarket AM143737 mower deck idler pulley assembly
Why Buy From PTO Direct USA?
- Fitment-first replacement-parts descriptions
- Clear OEM part-number and supersession routing
- Related mower deck belts, blades, spindles, and pulleys available
- Support for homeowners, repair shops, and landscape crews
Need Help Confirming Fitment?
Still not sure which deck pulley fits your mower? Contact us for fitment help and send a clear picture of the mower identification tag or the original pulley part number.
FAQ
What does AM143737 replace?
John Deere AM143737 replaces the earlier AM136693 mower deck idler pulley on compatible applications.
What are the approximate AM143737 pulley dimensions?
This aftermarket replacement has an outside flange diameter of approximately 5.92 inches, a center bore of approximately 0.66 inch, and an overall width of approximately 1.04 inches.
Why does John Deere list a 5-inch diameter?
John Deere publishes an approximately 5-inch effective diameter, which refers to the belt-contact area. The approximately 5.92-inch replacement measurement is taken across the outer pulley flanges.
Does AM143737 fit the John Deere Z425?
Yes. AM143737 is used in select John Deere Z425 48-inch and 54-inch mower deck configurations. Confirm the exact pulley callout because the deck can use several different idler positions.
Does AM143737 fit the John Deere Z435 and Z445?
Yes. AM143737 is used on select Z435 and Z445 48-inch and 54-inch mower deck paths. Match the mower serial or PIN range and deck diagram before ordering.
Is AM143737 the same as AM128118?
No. AM143737 and AM128118 are separate mower deck pulley paths with different physical dimensions and deck positions. See the AM128118 deck pulley listing when that number appears in the original diagram.
Is AM143737 the same as AM135526?
No. AM143737 and AM135526 are separate pulley numbers. Do not substitute them based on appearance or mower model alone.
Can I order this pulley by deck width?
No. A 48-inch or 54-inch John Deere deck can contain multiple idler pulleys. Match the exact OEM number and diagram position before ordering.