Seven-piece new solenoid set for 2004-up GM 4L80E and 4L85E: TCC/PWM, EPC, both shift solenoids, internal harness, filter and pan gasket.
If your 2004 or newer Chevy or GMC 2500/3500, Express or Savana van with the 4L80E or 4L85E is flaring between gears, shuddering at 45 to 60 mph, starting in the wrong gear, or throwing solenoid codes, this is the full electrical service for it. All seven pieces are new and listed by GM number: TCC/PWM solenoid 24210864, EPC pressure control solenoid 24248892, the 1-2 and 3-4 A shift solenoid 24230288, the 2-3 B shift solenoid 24230289, internal harness 24200161, filter with seal 24210956 and pan gasket 8677743. The listing covers RPO codes MT1 and MN8.
The 4L80E is a heavy-duty, four-speed, rear-drive automatic, and the control module runs it through four solenoids bolted to the valve body. The A and B shift solenoids are simple on/off valves. The module switches them in combination to stroke the 1-2, 2-3 and 3-4 shift valves, so a single weak solenoid can affect more than one shift. The EPC solenoid is different: it is a variable-force unit the module feeds with a changing current to set line pressure, which is what clamps every clutch and band. The TCC/PWM solenoid is pulsed to apply and release the converter clutch smoothly instead of slamming it on. Every one of them gets its signal through the internal harness, which is why the harness is in this kit and not sold as an afterthought.
Scan for codes first and write them down. A 4L80E that has already burned its clutches will not be cured by solenoids, so check the fluid condition and the line pressure before spending money. Line pressure that is low and will not rise with throttle points toward the EPC circuit, but Sonnax notes that a worn actuator feed limit (AFL) valve bore can also starve the solenoids of feed oil and produce the same complaint. Measure the shift solenoids too: Transmission Digest cites a 19 to 31 ohm range from the GM charts for this family of on/off solenoids. The steps for the pressure side are in our 4L80E EPC solenoid symptoms guide, and the broader list of what brings these units in is in 4L80E common problems and fixes.
This is the 2004-and-later kit for GM 4L80E and 4L85E transmissions. GM changed the internal wiring and the connector layout partway through production, and this 2004-up harness will not plug into a 1991-2003 unit. Read the RPO tag and look at the case pass-through connector before you order. Trucks built around the changeover are the ones most often ordered wrong, so if you are unsure, send us the year and VIN or compare your connector against the photos. Every part we carry for this transmission is on the 4L80E shop page.
Change all seven pieces in one pan drop. The labor is the same as replacing one solenoid, and leaving an old solenoid beside new ones is the usual reason a truck comes back. Drain the fluid, remove the pan and filter, and check that the old filter seal came out of the case. Unplug the harness, remove the solenoids, and keep track of which bore each one came from. Wet every new O-ring with ATF before seating it, route the new harness on the original path away from the filter, and inspect the pass-through connector tabs. Fit the 24210956 filter with its seal and the 8677743 gasket, torque the pan bolts evenly, and refill with Dexron VI. Clear codes, road test through all gears and lock-up, and recheck the level hot.
If the diagnosis shows a worn valve body, the 2004 4L80E valve body fits the same job. If the clutches are already slipping, pair the solenoids with the 4L80E banner kit with Raybestos frictions during a rebuild.
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Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
No. This kit is for 2004 and later units. The 1991-2003 4L80E uses a different internal harness and connector, so a 2002 truck needs one of our earlier-style kits. Check the RPO tag and the case connector, or send us the year and VIN.
Yes. The EPC solenoid sets line pressure. When it wears and pressure drops, the clutches slip, the fluid overheats, and the friction material burns. That is why replacing it early is cheaper than waiting for a slipping transmission.
Use Dexron VI ATF. GM rates Dexron VI as back-serviceable for transmissions that originally called for earlier Dexron fluids.
Clear the codes with a scan tool, then drive the truck through every gear and converter lock-up so the control module can adapt shift timing to the new parts. If your scan tool offers a reset of transmission adapts, use it before the road test.
It can be either. A failing TCC/PWM solenoid causes shudder and RPM that will not settle, often with P0741 or P1870. If the shudder stays after new solenoids and fresh fluid, the converter clutch itself is likely worn.
On a high-mileage truck, yes. The harness sits in hot fluid over the valve body for its whole life, and a chafed wire causes intermittent shift problems that look like solenoid faults. Replacing it with the solenoids clears the whole electrical side at once.
