4L60E Refurbished Solenoid Kit with TCC Harness, 1996-2002

If your 1996-2002 Silverado, Sierra, Tahoe, Suburban, Yukon, S10, Sonoma, Blazer or Camaro is stuck in one gear, refusing to lock the converter, or setting a string of solenoid codes, this is a budget way to renew the entire electrical side of the valve body in one pan drop. It is a refurbished set, not new: shift solenoid A, shift solenoid B, the 3-2 downshift solenoid, the TCC PWM solenoid, a Rostra EPC pressure control solenoid, a Rostra pressure switch manifold, and the TCC lock-up solenoid already attached to the internal wiring harness. The listed part reference is 24230298 / 34605A, and the set carries a 3-month warranty.

What this solenoid set does inside a 1996-2002 4L60E

The 4L60E picks its gears with just two on/off shift solenoids. The computer runs them in four combinations (both on for first, A off and B on for second, both off for third, A on and B off for fourth), and the shift valves simply follow that hydraulic signal. The EPC solenoid sets line pressure, the TCC solenoid and TCC PWM solenoid apply and feather the converter clutch, the 3-2 solenoid times the forced downshift, and the pressure switch manifold reports the manual valve position back to the computer. The harness ties all of it to the case pass-through connector. On a truck this age, every one of those parts has seen twenty-plus years of heat cycles, which is why replacing the group makes more sense than chasing them one at a time.

Symptoms this kit addresses

• Shift solenoid A codes P0751 or P0753: often starts in second, or holds a gear it should leave.
• Shift solenoid B codes P0756 or P0758: missing third and fourth, or a 1-4 style shift pattern.
• P0748 pressure control circuit: soft, slipping shifts or very harsh engagement into drive.
• P0740 or P1870: converter will not lock, or slips and shudders at highway speed.
• A flare or bang on the 3-2 kickdown, or intermittent limp mode that comes and goes with heat.

How to confirm the problem before you buy

Read the codes, then check the circuits at the case connector before blaming the solenoids. ATRA lists the 1-2 and 2-3 shift solenoids at 20-40 ohms and the pressure control solenoid at 3.5-8.0 ohms, measured across specific case connector pins. A reading far outside those ranges points inside the case; an open or short on the vehicle side points at the external harness instead. Our 4L60E shift solenoid symptoms and testing guide walks through the pin map and a road test. Be aware that a solenoid can pass a resistance test and still respond too slowly under load, which is one more reason to replace the set rather than the single part that set the code. If the code is P0748 specifically, read our P0748 pressure control solenoid guide first.

Fitment

This set is listed for the GM 4L60E built for model years 1996 through 2002 only. Earlier 1993-1995 units and 2003-up units use different solenoid and pressure switch layouts, so this harness will not plug in correctly on those. Before you order, pull the pan or look at photos of your valve body and match the harness routing, the pressure switch manifold shape and the solenoid connectors to the photos on this page. If you are unsure, send us your year and VIN and we will check it. Every other 4L60E part we carry is on the 4L60E parts page.

Install notes

• Drain the fluid, drop the pan, pull the filter, and unplug the case pass-through connector from inside the case.
• Remove the solenoid retaining clips and the bracket bolts, then lift the harness out with the solenoids still attached so you can see how it was routed.
• Coat every O-ring with clean ATF before seating each solenoid, and route the new harness exactly where the old one sat so it clears the filter.
• Fit a new filter and pan gasket, or a new pan such as the 4L60E pan with drain plug and gasket if yours is dented or rusted.
• Refill with Dexron VI ATF, the current GM fluid that supersedes the earlier Dexron specifications, and check the level hot.
• Clear codes and run the adaptive shift relearn with a scan tool. Skipping that step is a frequent cause of harsh shifts right after a solenoid job.

If new solenoids do not cure a slipping converter or shift flare, the valve body bores are the next suspect. A worn body cannot hold the pressure the new solenoids command, and the fix is a replacement such as our 4L60E valve body for 1998-2008.

Is this kit new or used?

It is refurbished. The solenoids, pressure switch manifold and harness are reconditioned parts and carry a 3-month warranty. If you want new parts, look at the new master solenoid kits on our 4L60E page.

Will it fit my 1995 or 2003 truck?

No. It is listed for 1996-2002 4L60E only. The 1993-1995 and 2003-up units use different solenoid and pressure switch layouts, so the harness and manifold will not match.

Why does it include a harness?

The internal harness gets brittle from heat, and a cracked wire throws the same intermittent solenoid codes as a bad solenoid. Replacing it with the solenoids takes it off the suspect list in the same pan drop.

Do I need a scan tool after installing it?

Yes. Clear the codes and perform the adaptive shift relearn. Without the relearn the computer keeps the old shift adaptations and shifts can feel harsh or erratic for a while.

What fluid should I use?

Dexron VI ATF. Fill to the correct level with the fluid at operating temperature after the install.

• 4L60E Shift Solenoid Symptoms, Testing and Replacement
• 4L60E P0748: Pressure Control Solenoid Failure - Causes, Diagnosis, and Fix
• 4L60E TCC Solenoid and Code P0740: Diagnosis and Replacement
• 4L60E 3-2 Downshift Solenoid and Code P0785: What It Really Means