Sonnax 105740-05K LPC Signal Damper Piston Kit for GM 10L80 10L90 Gen 2

The Sonnax 105740-05K LPC Signal Damper Piston Kit is engineered to correct LP signal (EPC) circuit pressure variation in GM Gen. 2 10L80 and 10L90 automatic transmissions. This drop-in replacement kit restores proper damping function to the lower valve body without requiring any reaming or valve body modification.

The LPC signal damper is responsible for smoothing out fluid pressure spikes in the LP signal (EPC) circuit before they can reach the main pressure regulator valve. When bore or piston wear occurs, effective dampening is lost, allowing pressure to leak to exhaust. This results in harsh shifts, erratic line pressure behavior, and excessively high main line pressure. The Sonnax 105740-05K kit addresses these issues with a precision-engineered drop-in replacement that outlasts the original equipment design.

Key Features:

• No reaming required — installs directly into the existing bore for a quick, long-lasting repair
• Hardcoat anodized aluminum piston — resists premature wear for extended service life
• Annular groove on piston — reduces wear rate over time
• Highly wear-resistant sleeve — protects the bore from future wear
• O-ring seal — provides a positive seal against critical pressure loss, even in already-worn bores

The Sonnax 105740-05K LPC signal damper piston kit is the professional transmission rebuilder's solution for correcting EPC circuit pressure variation in GM Gen. 2 10-speed transmissions, eliminating the need for costly valve body replacement.