Replaces the shift A/B, 3-2, TCC, TCC PWM and EPC solenoids plus the internal harness on a 1993-2002 GM 4L60E in one swap at the valve body.
When a 1993-2002 Silverado, Tahoe, S10, Camaro or Sierra starts taking off in second, refuses to come out of third, flares on a part-throttle 3-2 downshift, or sets P0748, P0753, P0758 or P0785, the problem is very often electrical rather than mechanical. This kit replaces every solenoid on the valve body side of the 4L60E at once, pre-mounted on a new internal wiring harness: shift solenoids A and B, the 3-2 downshift solenoid, the TCC on/off solenoid, the TCC PWM solenoid and the EPC pressure control solenoid.
The 4L60E uses just two on/off shift solenoids to select all four forward gears. Shift solenoid A (1-2) and B (2-3) are both on in first, B alone in second, both off in third and A alone in fourth. If either one sticks or loses its circuit, the computer commands a gear the hydraulics cannot produce. The EPC solenoid is a variable-force unit that sets line pressure for every shift, the 3-2 solenoid times the release on downshifts, and the TCC and TCC PWM solenoids apply and modulate converter lockup. All of them share a single 12-volt feed, circuit 1020, through the internal harness, which is why one tired harness can set several codes at once.
Unplug the case connector and measure through the pins. ATRA's published 4L60E values are 20-40 ohms for each shift solenoid and the TCC solenoid, 9-14 ohms for the 3-2 solenoid and 3.5-8.0 ohms for the EPC solenoid. A reading out of range, or one that changes when you flex the harness, confirms the electrical side. If every solenoid reads correctly and the shift complaint remains, the fault may be bore wear in the valve body instead. Our 4L60E shift solenoid testing guide walks through the full pin map, and the P0748 pressure control solenoid guide covers EPC-specific diagnosis.
This kit is laid out for the 1993-2002 style 4L60E and 4L65E valve body and harness, as used in Chevrolet, GMC and Cadillac trucks, SUVs and cars of that era. Cross references include GM 10478120, 24230298, 24219581, 24220158, 24203101, 8684216, 24227792 and 24212327. The 2003-up 4L60E uses a different harness layout, so for a 2003 or newer truck choose the 4L60E solenoid kit for 2003-2007 instead. Compare your harness routing and connector to the photos, or send us your year, model and VIN and we will confirm. Everything else we stock for this unit is on the 4L60E parts collection page.
The work is done in the vehicle. Drain and drop the pan, pull the filter, then release the case connector by squeezing its two tabs and pulling straight up; do not pry it with a screwdriver, which bends pins. Unclip the solenoids and harness retainers, lift out the old assembly as one piece and lay the new one in its place, checking every solenoid O-ring is seated in its bore. Reconnect the case connector by lining up the arrows and pushing straight down until it clicks. Fit a new filter and pan gasket, a 4L60E pan, filter and gasket kit works well if the stock pan is bent, then refill with Dexron VI, clear codes and road test through every gear and a 3-2 downshift.
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Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
No. It is laid out for the 1993-2002 4L60E and 4L65E harness. GM changed the harness layout for 2003-up units, so a newer truck needs the 2003-and-later solenoid kit.
ATRA lists 20-40 ohms for each shift solenoid and the TCC solenoid, 9-14 ohms for the 3-2 control solenoid and 3.5-8.0 ohms for the pressure control solenoid, measured at the case connector.
All the solenoids share the circuit 1020 power feed through the internal harness. A poor crimp or heat-cracked wire there can set P0740, P0753, P0758, P0785 and P1860 together, so replacing one solenoid often leaves the real fault in place.
No. The pan, filter, solenoids and internal harness are all serviced from underneath with the transmission in the vehicle.
Dexron VI. Replace the filter and pan gasket at the same time, then clear codes and road test through every gear.
