The Coan Racing COA‑12042 Pro‑Tree 4/5 Trans‑Brake Replacement Valve & Spring is a meticulously crafted, direct-fit component designed to restore high-performance launch control functionality in GM Powerglide transmissions.

This precision-engineered assembly replaces worn or missing factory valve and spring components, providing consistent hydraulic modulation required for “Pro‑Tree” drag racing setups. Built to Coan’s race-proven quality standards, the COA‑12042 ensures leak-free, reliable trans‑brake engagement and seamless integration into manual valve bodies.

Whether you’re refreshing a stock transmission or equipping a full-race unit, this valve and spring kit delivers the consistent, repeatable performance needed to maintain crisp and confident trans‑brake operation under aggressive, high-stress conditions.