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Manufacturer Part Number: SK 6T40-A

Other Part Number: T144165A, T46165A

Brand: Transgo

Shift Kit®
Fits all 6T30, 6T40, 6T45
GEN1 2007-2012
with pressure switches

This 6T40-A Shift Kit fits 2007 to 2012 GM vehicles equipped with GEN1 6T30, 6T40 and 6T45 automatic transmission. These transmissions often come in with complaints of soft or flare up on shifts, burned friction plates, TCC slip as well as various solenoids and gear ratio codes. This kit does not fit GEN2 units.

These complaints are often the result of wear at the actuator feed limit (AFL) valve. The purpose of the AFL valve is to limit the pressure going to the solenoids. The AFL valve spring is calibrated to prevent the solenoid feed pressure from exceeding a predetermined PSI, no matter what main line pressure is. This is necessary to prevent more fluid from being fed to the solenoids than they can effectively regulate and limit what max line pressure output is. If the pressure feeding the solenoids is too high or too low, their output will also be too high or too low. As a result, shift quality complaints and codes can occur along with low or high main line pressure.

The other source of these complaints is at the spring end of the pressure regulator valve and or bore. This is the EPC boost signal area of the valve. When bore or valve wear occurs here the EPC boost signal oil is lost. The end result is lazy pressure boost response, low line pressure, clutch slippage and solenoid performance as well as gear ratio codes. Lastly, the TCC regulator valve bore wears out causing the TCC slip problems and codes.

Features and benefits:

This TransGo Shift Kit includes a new drop-in AFL valve system. The furnished bushing, valve, spring, spacer and retainer will restore the AFL function using the existing worn bore. For the TCC regulator valve, a drop-in hardened steel valve with re-positioned longer lands that uses a scarf cut sealing ring so that it can seal in the original worn bore. Similarly, a new design PR valve with longer lands restores the function and reliability of the line PR system. Lastly, the kit includes new O-rings and diaphragms to renew the TEHCM pressure switches.


  • Erratic or hunting TCC
  • Soft shifts or flare up on shifts
  • Burned friction plates
  • Slow pressure boost response
  • Codes P0741, P0751, P0752, P0757, P0776, P0777, P0796, P0797, P0842, P0843, P0872, P0873, P0877, P0878, P0989, P0990, P2714, P2715, P2723 and P2724


  • Drop-in USA-made hardened steel PR valve and spring
  • USA-made hardened steel AFL valve
  • Drop-in USA-made steel AFL bushing
  • ALF valve spring, spacer and retainer
  • Drop-in USA-made hardened steel TCC regulator valve
  • TCC regulator valve scarf cut sealing ring, spring and O-ring (for sizing only)
  • (4) Pressure switch diaphragms
  • (4) Pressure switch O-rings

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