Transgo 4L6-ISO-3 Transmission Valve Kit, Torque Converter Clutch (TCC)

1995 to 2015 General Motors vehicles equipped with a 4L60E, 4L65E and 4L70E SERTA (Service Replacement Transmission Assembly) remanufactured transmission often come in with complaints of TCC slip or shudder, code P1870 or P0894 and harsh 1-2 shift.

The torque converter clutch regulator valve bore is very prone to wear causing the TCC slip complaints and related code. The TCC slip code leads to the harsh 1-2 upshift as the ECM recognized the TCC slip and commands high line pressure to avoid further TCC slippage and damage. For that reason, GM remanufactured SERTA transmissions usually have valve bodies that have been machined to allow the use of a larger .472” diameter TCC regulator and isolator valve. Over time those wear out the bore the same way the originally valve did, again leading to the same complaints.

This TransGo 4L6-ISO-3 kit features a drop-in USA-made hardened steel, oversized patented isolator valve. The redesign valve restores the hydraulic integrity of the circuit by utilizing previously unused and therefore unworn areas of the bore. In addition, it can be used without the included spring to work in vehicles with active fuel management (AFM). Lastly, this kit includes enough parts to fix three transmissions.

• TCC slip or shudder
• Code P1870 and P0894
• Harsh 1-2 shift
• Reduces future wear

• (3) Drop-in USA-made hardened steel over-sized isolator valves
• (3) Isolator valve springs