4L80E Master Solenoid Kit with Harness, Filter and Gasket

A full electrical service for the GM 4L80E and 4L85E (RPO MT1 and MN8) from 1997 to 2003. The kit includes the TCC/PWM solenoid (24210864), EPC solenoid (24220158), 1-2/3-4 shift solenoid A (24230288), 2-3 shift solenoid B (24230289), the internal wiring harness (24222798), plus a fluid filter with seal (24210956) and the pan gasket (8677743). New parts, not salvage.

Harness failures on these units are common: the internal harness gets brittle and cracks at the connectors, which throws intermittent solenoid codes and random limp mode that a single solenoid swap will not fix. A worn TCC/PWM solenoid causes highway shudder and RPM flare at lockup, and a tired EPC drops line pressure, which lets the clutches slip and cook. This kit covers all of it in one pan-off job.

Install: drain and drop the pan, remove the filter, unplug and pull the old harness and solenoids, clean the pan and magnet, install the new solenoids with fresh O-rings lubed in ATF, route the new harness the same way as the old one and clip it down, then fit the new filter and gasket. Refill with Dexron VI, clear codes and verify shift and lockup on a road test.