BILLET ALUMINUM FWD/DIR PISTON (.555") W/ CHECKBALL

The Coan Racing COA‑22830D Billet Aluminum Forward/Direct Piston (.555″) with Checkball is a precision-engineered upgrade designed to improve the robustness and hydraulic consistency of direct drum assemblies in TH400 transmissions. Machined from premium billet aluminum in the USA, the .555″ piston size maintains an optimal fluid volume and its increased material strength enhances sealing performance under high-pressure shifts. Equipped with an integrated checkball, it ensures positive hydraulic control to prevent fluid backflow at launch and during gear engagements.

The COA‑22830D installs seamlessly without the need for drum or case modifications. This piston offers builders a refined front-end solution that delivers durability, consistent clutch application, and race-ready reliability in aggressive street, drag, or bracket-car setups.