2 Pack GY22172 Idler Pulley with GY20629 Idler Pulley Replace AUC17621 GY22082 GY20067 GY20110 for John Deere S140 S160 S170 E140 E150 E160 E170 LA145 LA165 L120 L130 D140 D155 D160 Mowers

What It Is

This 2-pack replaces the GY22172 and GY20629 idler pulleys used on the mower deck drive belt system for select John Deere lawn tractors. It’s a direct-service part for maintaining belt tension and smooth blade engagement on residential Z-Series and 100-series mowers.

Fitment & Compatibility

Before buying, verify:

• Model check: Fits John Deere S140, S160, S170, E140, E150, E160, E170, LA145, LA165, L120, L130, D140, D155, D160. Not for X-series or zero-turn models.
• Deck size: Works with 42", 48", and 54” decks that use dual idler pulleys (check your deck diagram).
• OEM cross-reference: Replaces OEM parts AUC17621, GY22082, GY20067, GY20110. If your original pulley has a different number (e.g., GY20838), measure outer diameter and shaft bore before buying.
• Physical specs: Each pulley has a 4.5” outer diameter, 0.5” bore, and 0.375” belt width. Measure your old pulley to confirm.
• Aftermarket note: This is a non-OEM replacement. It’s functionally identical but may have slightly different bearing branding.

Key Things to Know

• Installation difficulty: Easy – 15 minutes with basic hand tools (socket wrench, possibly a pry bar to relieve belt tension). No special skills needed.
• Common gotcha: The pulley bolts are often seized. Use penetrating oil (WD-40 or PB Blaster) and a breaker bar. Don’t overtighten – torque to 20–25 ft-lbs.
• Quality check: Bearings are sealed (not serviceable). If you hear noise after 2 seasons, replace again – typical for budget pulleys.
• Double-check quantity: This is a 2-pack of the same pulley (GY22172/GY20629). Some decks use one of each – verify your deck uses two identical pulleys.

Should You Buy It

Yes, if you need a quick, affordable fix for a worn idler pulley on a common John Deere lawn tractor. It’s a no-frills aftermarket replacement that works well for light-to-moderate use. Skip it if you want OEM branding or have a high-acreage commercial mower – go with a genuine John Deere pulley for longer life.