The Speedmaster PCE222.1007 Stage 2 Shift Improver Kit is designed for GM Turbo 400 (TH400), TH375, and M40 automatic transmissions, delivering firmer, more precise gear changes that reduce clutch pack slippage and improve overall drivetrain response. Stage 2 calibration targets performance-oriented driving where crisper, more aggressive shifts are desired over the factory soft shift profile.
This kit provides an accessible upgrade path for enthusiasts looking to extract better performance and longevity from their TH400-family transmission without a full rebuild. Engineered to work within the existing valve body architecture, the included components help restore or enhance hydraulic shift quality, making it a practical addition for street performance, hot rod, and light competition applications.
