All five electronic solenoids for a 2003-up GM 4L60E or 4L65E: 1-2 and 2-3 shift, 3-2 downshift, EPC and TCC PWM, replaced in one valve body job.
A 2003-or-later GM truck with a 4L60E or 4L65E that starts out in second, refuses to upshift, thumps on a 3-2 kickdown or never locks the converter is usually telling you something about its valve body solenoids. This kit replaces all five electronic solenoids on the late-model valve body in one job: shift solenoid A (1-2), shift solenoid B (2-3), the 3-2 downshift solenoid, the EPC pressure control solenoid and the TCC PWM solenoid. It suits the Chevrolet Silverado 1500, Tahoe, Suburban and Avalanche and the GMC Sierra 1500 and Yukon that came with these transmissions, provided the unit is a 2003-up design.
Think of each solenoid as a switch for one hydraulic decision. ATRA's solenoid application chart lists the 4L60E as a two-solenoid shifter: A and B both on for first, A off and B on for second, both off for third, and A on with B off for fourth. That pattern is useful for diagnosis, because a solenoid that sticks in one state locks the transmission into a predictable gear. The EPC solenoid works differently: the computer varies its current to raise or lower line pressure, which sets how firm every shift feels. The TCC PWM solenoid pulses to bring the converter clutch on gradually, and the 3-2 solenoid manages the hand-off between the 3-4 clutch and the 2-4 band on downshifts. Sonnax notes that all of them are fed from the actuator feed limit circuit at roughly 115 psi in this family.
Look at two things first. Check the fluid and pan for metal or clutch material, because a solenoid kit will not fix worn clutches, and inspect the internal harness and its connectors for heat damage. A Transmission Digest case study on a 4L60E-equipped S-10 is a good warning: the shift solenoid measured within GM's resistance spec but responded too slowly, and only a road test with gear ratios on a scan tool caught it. On the 3-2 side, Sonnax points out that the 3-2 control valve spring in late valve bodies often breaks, causing a 3-2 bind and an overheated 2-4 band that no solenoid will cure. Our shift solenoid A and B code guide and the P0785 3-2 solenoid guide go deeper.
This kit is listed for GM 4L60E and 4L65E transmissions from 2003 and later. The 1993-2002 transmissions used different solenoid and connector styles and are not covered. Model year and transmission build date do not always line up on trucks built near the changeover, so pull up the connector shape and numbers on your current solenoids, or give us your year and VIN to verify. Other parts for this transmission are on the 4L60E collection page.
If the harness is brittle or a connector is burnt, replace it now rather than chase the same codes later; trucks in that range can use the 4L60E internal wiring harness for 2006-08. An aluminum pan kit with filter and magnetic drain plug turns future fluid changes into a drain-and-fill instead of another pan drop.
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Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
This listing calls out the 4L60E and 4L65E for 2003 and later. If you have a 4L70E, compare the numbers on your solenoids or send us the year and VIN before ordering.
It can be. A shift solenoid stuck in the wrong state, or a broken feed wire to it, changes the on/off combination the valve body sees and can leave you starting in second or third. Check the wiring and connector before replacing parts.
A new filter and pan gasket at minimum. If the internal harness is heat-cracked or a connector is burnt, replace it at the same time, since a bad harness sets the same codes as a bad solenoid.
If the 3-2 solenoid is the cause, yes. But a broken 3-2 control valve spring in the valve body is a known cause of 3-2 bind on late units, so inspect the valve body if the problem stays.
Dexron VI ATF. Check the level hot, engine running, in park.
