Seven-piece pan-off service set for 2004-up GM 4L80E and 4L85E: A/B shift, EPC and TCC solenoids plus internal harness, deep-pan filter and gasket.
This is the pan-off electrical set for late-style GM 4L80E and 4L85E transmissions in 2004 and newer heavy-duty Chevrolet and GMC pickups, Suburban 2500s and Express or Savana vans. If your truck will not upshift, is stuck in one gear, shifts hard or late, or will not lock the converter, and the scan tool points to the electronics, this kit replaces every part involved in one job. Inside the box are both A/B shift solenoids, the EPC pressure control solenoid, the TCC/PWM lock-up solenoid, the internal wiring harness, a deep-pan filter and a pan gasket. The whole kit weighs about 2.4 lb.
Think of the valve body as the plumbing and these parts as the switches that run it. The A and B solenoids open and close to tell the shift valves which gear the module wants. The EPC solenoid controls how hard the clutches are squeezed by adjusting line pressure from moment to moment. The TCC/PWM solenoid applies the converter clutch gradually at cruise. All of them are fed oil by the actuator feed limit valve and fed current by the internal harness, so the kit works best when the oil supply and the wiring are both healthy.
Scan the truck before buying anything, and be honest about what solenoids can fix. They will not repair burnt clutches, a worn valve body or a transmission that is low on fluid. Check the fluid level and smell first. Then look at line pressure. Sonnax explains that the EPC solenoid keeps oscillating the AFL and torque signal oil, which speeds up wear in the AFL valve bore. Once that bore wears, feed pressure to every solenoid drops and the truck acts like it has bad solenoids even after new ones go in. If pressure stays low with a new EPC solenoid, the valve body needs attention. Our EPC solenoid symptoms guide covers the pressure test, and Sierra 2500 common problems lists what else fails on the GMC side.
Fits GM 4L80E and 4L85E transmissions from 2004 on that use the late-style EPC connector and case pass-through plug. It does not fit the early 1991-2003 harness design, and it is not for Jaguar applications of this transmission. The fastest way to be sure is to compare three things against the product photos: the plug on your old EPC solenoid, the pass-through connector at the case, and the shape of your filter. If any of them look different, send us your year and VIN before ordering. The rest of our parts for this unit are on the 4L80E shop page.
Drain the fluid and remove the pan, then pull the filter. Unplug and unbolt the solenoids and the harness from the valve body, and release the pass-through at the case. Put the new harness in first so you are not working around solenoids. Give each solenoid O-ring a light film of ATF, seat the solenoids, and torque the retainers. Install the deep-pan filter, lay on the new gasket, and torque the pan bolts evenly. Refill with Dexron VI, clear the codes, and road test through every gear and lock-up before checking the level hot.
If you find debris or worn bores while the pan is off, the 4L80E valve body check ball kit and the valve body end plug kit handle the hydraulic side the solenoids depend on.
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Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
Compare your EPC solenoid plug, the case pass-through connector and your filter against the product photos. The 2004-up units use a late-style EPC connector and pass-through plug. If you are unsure, send us the year and VIN.
Only if the slip comes from low line pressure caused by the EPC circuit. If the clutches are already burnt, the valve body is worn or the fluid is low, solenoids will not fix it. Scan and pressure test first.
Yes. The kit includes a deep-pan filter and a pan gasket along with the four solenoids and the internal harness.
No. This kit is not for Jaguar applications. It is for GM 4L80E and 4L85E transmissions from 2004 on.
Use Dexron VI ATF, then road test and check the level hot.
