John Deere M126636 Extension Spring is a John Deere equipment manufacturer (OEM) part, also known as a Traction Drive Belt Tightener Spring. This high-quality extension spring is designed to fit various John Deere models, including LT150 with Hydrostatic Transmission, LT155, LT160, LT166, LT170, LT180, LT190, LTR155, LTR166, and LTR180. Engineered for durability and reliable performance, it helps maintain proper tension on the traction drive belt, ensuring smooth operation of your equipment. For assistance in finding the right John Deere part or accessory, John Deere specialists are available Monday through Friday, from 8:00 AM to 5:00 PM (EST) at 800-345-2396, or via email through the contact link provided. Hartville Hardware strives to provide accurate parts information sourced from reliable systems, but compatibility may change without notice, so contacting customer support is if you are unsure about the part you need.