6L80 Pressure Switch Repair Kit 124740-30K, 40 Discs and Seals

This is a bulk refill kit for the pressure switches on the GM 6L80 control solenoid valve body (the TEHCM that bolts to the bottom of the valve body). You get 40 laminate diaphragm discs and 40 seals, enough to rebuild every switch on several units. It is the same repair as part number 124740-30K and also crosses to S124442RK-1 and 124740-70K. It fits the 6L45, 6L50, 6L80 and 6L90 rear-drive six-speeds and the 6T70 and 6T75 front-drive units, found in Silverado, Sierra, Tahoe, Yukon, Escalade, Enclave and many other GM trucks and SUVs.

Each pressure switch uses a thin laminate disc and a seal to separate fluid pressure from the switch contacts. Over time the disc wears or tears and the seal hardens. The switch then leaks, sticks or reports the wrong state to the TCM. Typical results are pressure switch codes such as P0842, P0872 or P0877, harsh or delayed shifts, or the unit dropping into limp mode. A new TEHCM is expensive, and in many cases the electronics are fine and only the disc and seal have failed.

On the bench, drop the pan, remove the TEHCM and clean it. Remove the retainer on the switch, pull the old disc and seal, install a new disc and seal, and restake or reseat the retainer so it holds tight. An installer tool such as the 124740-TL30 makes seating the new parts much easier. After reassembly, clear codes and reset the transmission adapts with a scan tool.

Note: this kit fixes mechanical disc and seal failures only. Check the switch circuit and connector with a meter first. If the switch has an open or shorted circuit, it will not be fixed by new rubber.