1A646025810 Transmission Drive Pulley 4.25 OD for Tuff Torq K46 K57 Husqvarna

This Transmission Drive Pulley is a replacement pulley compatible with Tuff Torq K46 and K57 transaxles and matches OEM Part# 1A646025810.

Product Overview

The Transmission Drive Pulley (1A646025810) is engineered to replace a worn or damaged input pulley on Tuff Torq K46 and K57 hydrostatic transaxles. This 4.25" OD drive pulley restores positive belt grip, eliminating slip and maintaining consistent ground speed on Husqvarna mowers and tractors equipped with those transmissions. A rugged direct bolt-on solution that gets the transmission drive system back to factory spec.

Key Features & Performance

• Replaces OEM part number 1A646025810 with exact 4.25-inch outer diameter
• Precision-machined bore and keyway for a secure press-on fit
• Engineered to handle high-torque loads generated by K46/K57 transaxles
• Restores correct belt alignment and tension to maximize belt life
• Heavy-duty construction resists deformation and cracking under heat
• Swift installation without special tools—designed as a direct drop-in replacement

Fitment & Compatibility

• Tuff Torq K46 transaxle models
• Tuff Torq K57 transaxle models
• Husqvarna lawn tractors and zero-turns equipped with Tuff Torq K46 or K57 (verify serial number break)

Common Uses

• Replacing a damaged or worn transmission input pulley on K46/K57 hydrostatic transaxles
• Restoring proper belt grip to eliminate slipping under load or on inclines
• Transmission service repairs on Husqvarna riding mowers
• Preventative upgrade when moving from a plastic factory pulley to a durable steel pulley

Technical Specifications

• Part Number(s): 1A646025810
• Outer Diameter: 4.25 inches
• Compatible Transaxle Models: Tuff Torq K46, K57

Frequently Asked Questions

Q: What is the significance of the 4.25-inch OD? A: The outer diameter matches the factory specification to ensure correct belt speed and tension on Tuff Torq K46 and K57 transmissions, preventing slippage and inconsistent drive performance.

Q: Will this pulley fit any Husqvarna with a K46 transmission? A: Yes, it is designed for Tuff Torq K46 and K57 transaxles commonly used in numerous Husqvarna models. Always confirm your original part number (1A646025810) and transaxle tag before ordering.

Product appearance and specifications may vary slightly by batch. Compatibility may vary by serial number. Verify fitment before purchase.