4L80E Transmission Solenoid Kit, EPC, Shift A/B and TCC

This set covers the four electrical control solenoids in a GM 4L80E (RPO MT1) from 1991 through 2003: the EPC force motor (24243101), shift solenoid A (24230288), shift solenoid B (24230289) and the TCC solenoid (24210864). It is the same group of parts a shop replaces when the valve body is out and the solenoid history is unknown.

Typical reasons to change them: stuck in one gear or limp mode from a failed A or B solenoid (P0753, P0758), harsh or soft shifts and slipping from a weak EPC that is not building line pressure (P0748), and converter lockup that will not engage or cycles on the highway (P0740). On a high-mileage unit it is cheaper to swap all four at once than to chase them one at a time.

On the bench: drop the pan and filter, unplug the internal harness at each solenoid, pull the retaining clips or bolts, and remove the old units. Check the solenoid screens and the valve body bores for debris, lube the new O-rings with ATF, seat each solenoid fully, reinstall the retainers and harness, then fit a new filter and pan gasket. Clear codes and road test through all four gears and lockup.