Sonnax 77754-03K TCC Regulator Isolator Valve Kit for Transmissions - 4L60E 4L65E 4L70E

The Sonnax 77754-03K TCC Regulator and Isolator Valve Kit is designed to restore proper torque converter clutch operation in GM 4L60-E, 4L65-E, and 4L70-E automatic transmissions. This kit addresses severe wear in the TCC regulator valve bore caused by oscillation of the OE valve, which allows regulated converter apply pressure to exhaust—a primary cause for TCC-related slip code P1870 and overheated converters.

Key Features:

• Provides 10% higher apply pressure for improved TCC performance
• Includes highly wear-resistant aluminum sleeve to restore hydraulic integrity
• Hardcoat anodized aluminum valves combat premature wear
• Isolator valve lengthened to operate in unworn portions of the bore
• Annular grooves help center valves in bore to reduce future side-load wear
• Restores normal TCC operation by shoring up hydraulic integrity of the circuit

Application: Fits 1997 and earlier non-EC3 units only. Designed for both PWM and non-PWM transmissions.

Installation Note: Requires bore reconditioning with proper reaming tools (F-77754-TL4 tool kit recommended). This kit prevents exhausting of apply pressure that can diminish line pressure and result in burnt clutches.