TH700R4 Transmission Torque Converter Lock-Up Kit

This Painless lock-up kit is designed to simplify and properly control the torque converter clutch (TCC) on GM TH700R4 automatic transmissions used from 1981–1993. It eliminates the need for factory computers or expensive standalone controllers and works with both carbureted and fuel-injected engines.

The included vacuum switch and 4th-gear pressure switch manage the TCC lock-up engagement automatically, ensuring smooth operation, reduced engine RPM, and improved fuel economy during cruising. The kit uses the early-style square Weather Pack connector found on 1981–1990 TH700R4 units (also known as early 4L60 before the change to the round 5-pin connector).

All wiring is clearly labeled, color-coded to Painless standards, and long enough for flexible routing. The system integrates through the brake switch for safety—unlocking the converter whenever the brake pedal is pressed.

Compatible with:
• Any engine (carbureted or fuel-injected)
• GM TH700R4 transmissions with early square connector (1981–1990; also labeled 4L60 1990–1993)

Kit Includes:
• Vacuum switch
• 4th-gear pressure switch
• Brake switch
• Torque converter lock-up solenoid
• Complete wire harness (11 ft overall)
• New transmission pan gasket
• Mounting hardware

Connections Provided:
• TCC solenoid to 4th-gear pressure switch
• TCC solenoid to main case pass-through connector
• Pass-through connector to vacuum switch
• Vacuum switch to 4-pin brake switch
• Brake switch to 20-amp fused power source

A complete, all-in-one solution for proper TH700R4 torque converter lock-up functionality.