Replaces the EPC, TCC, PWM, 3-2 and A/B shift solenoids plus the internal harness on 2003-2005 GM 4L60E valve bodies in a single pan drop.
Harsh 1-2 shifts that slam the truck forward, soft shifts that flare, a converter that will not stay locked on the highway, or a P0748, P0960 or P0741 on the scan tool: those are the complaints that send 2003-2005 GM truck, van and SUV owners looking for a 4L60E solenoid kit. This one focuses on the solenoids that control pressure and lockup as well as the shift pair. It includes the EPC pressure control solenoid, the TCC and PWM solenoids, the 3-2 downshift solenoid, shift solenoids A and B, and a new internal wiring harness to connect them to the case.
Most of the solenoids in a 4L60E are simple on/off valves. The EPC solenoid is the exception. The computer varies the current to it continuously to raise or lower line pressure, and line pressure decides how firmly every clutch and band applies. When the EPC wears, its output drifts, so the same shift that should feel crisp either bangs or slides. That is why EPC wear and P0748 are some of the best-known faults on this transmission. The TCC solenoid enables the converter clutch and the PWM solenoid controls how gradually it applies, so a weak one shows up as shudder, slip or no lockup. Shift solenoids A and B pick the gear, and the 3-2 solenoid controls the timing of the 3-2 downshift. Replacing all of them together with the harness means every part in the circuit starts with the same mileage.
Pressure-related symptoms have two common sources: the EPC solenoid itself, or worn valve body bores leaking the pressure it commands. Start with the electrical side. Check the EPC circuit and solenoid resistance at the case connector using our EPC pressure control solenoid guide, and work through converter lockup problems with the TCC solenoid and P0740 guide. If the solenoids and wiring check out and the shift feel or TCC slip continues, the valve body needs a vacuum test. Sonnax has long pointed to bore wear in this family as a cause of shift-feel and lockup complaints that new solenoids alone will not fix.
This listing is for GM 4L60E transmissions in 2003-2005 trucks, vans and SUVs. The listing notes that 2003-up units use a different TCC/PWM and harness arrangement from 1993-2002 transmissions, so an early truck needs a different kit. Confirm your build date and compare the connectors on your valve body to the photos before ordering, or send us your year and VIN to have it checked. The kit weighs 3.65 lb. Unlike some of our other kits, a filter and pan gasket are not listed as included, so order them for the same job. If you would rather get everything in one box, the 2003-2005 solenoid kit with harness, filter and pan gasket includes them. The full lineup is on the 4L60E parts page.
If the vacuum test shows bore wear, a 2003-2009 4L60E valve body is the cleaner fix than chasing individual valves.
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Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
No. The listing covers the six solenoids and the internal harness only. Buy a filter and pan gasket for the same pan drop, or choose our 2003-2005 kit that includes both.
No. The listing states that 2003-up units use a different TCC/PWM and harness arrangement than 1993-2002 transmissions. Early trucks need a 1993-2002 kit.
They will if the EPC solenoid or its wiring is the cause. If the valve body bores are worn, pressure leaks past the valves no matter how good the solenoid is. Test the EPC circuit first, then vacuum test the valve body if the complaint continues.
It means the computer sees the converter clutch slipping or not applying when it has been commanded on. A worn TCC or PWM solenoid can cause it, and so can valve body bore wear in the converter circuit, so confirm the solenoids before replacing more parts.
Yes. Clear the stored codes and run a shift relearn. The computer learned its shift adapts around the worn EPC, so it has to relearn them with the new solenoid.
