4L60E Master Solenoid Kit with Internal Harness, 1993-2002

This is a complete electrical refresh for the 1993-2002 GM 4L60E: the 1-2 and 2-3 shift solenoids (A and B), the 3-2 control solenoid, the TCC on/off solenoid, the TCC PWM solenoid, the pressure control (EPC) solenoid, and the internal wiring harness that ties them to the case connector. Replacing the whole set at once makes sense when the unit is out or the pan is down, because the solenoids share the same age, heat history and harness.

Typical reasons to do it: P0750/P0755 shift solenoid codes, P0740 or P1870 TCC codes, a 3-2 downshift flare, no lockup, harsh or delayed engagement from a weak EPC, or a harness with cracked insulation and burned pins at the pass-through connector. When one early 4L60E solenoid fails, the others are usually close behind.

On the bench: drain and drop the pan, pull the filter, unplug the harness at each solenoid and the pressure switch manifold, and remove the retaining clips and bolts. Install the new solenoids with fresh O-rings lubricated in ATF, route the new harness along the original path so nothing rubs the valve body, torque the solenoid bolts to spec, and refill with DEXRON. Clear codes and road test through all shifts and lockup.

Cross-references GM part numbers 10478112, 10478120, 10478131, 24230298, 24215111, 24219581, 24220158, 24203101, 24209276, 8677314, 8684216, 24212690, 24227792, 8683187, 24212327, 24203267 and 24209121. It is built for 1993-2002 units; 2003-and-later 4L60E and 4L65E transmissions use a different EPC and harness, so check your build year before ordering.