8L45 Tcc Solenoid, remanufactured and ready to install. Fits the 8L45. Ships fast from the USA.
A remanufactured TCC solenoid is the budget way to bring back converter lockup on a GM 8L45 when the original has been flagged by a P0741 or P0742 code, or the engine is spinning higher than it should at a steady 60 mph. This unit is tested and ready to install, carries reference number 24272280, and is listed for 8L45 applications including the Cadillac CT6 as well as GM's mid-size trucks and rear-drive cars that use this 8-speed.
The 8L45 is the lighter-duty member of GM's 8-speed family, but it shares the same control layout as the 8L90. The torque converter clutch is run by S7, a variable force pressure control solenoid rated normally low. The TCM varies current to the solenoid, the solenoid turns that current into signal pressure, and a clutch control valve in its own bore converts the signal into converter clutch apply pressure. Like every pressure control circuit in this valve body, the S7 signal passes through a small signal accumulator that smooths the pressure. When the solenoid sticks, wears or leaks internally, the TCM cannot hold the slip target it commands, so it either sets a code or gives up on lockup.
Start with a resistance check at the solenoid: the pressure control solenoids on this unit are specified at 4.5-5.5 ohms, and an open or shorted reading settles the question. If resistance is good, look harder at the hydraulics. Sonnax points out that every VFS circuit in this valve body has a signal accumulator, and wear in those bores creates complaints that are easy to blame on the solenoid. A shudder only at steady cruise with no code is usually the fluid issue GM covered in bulletin 18-NA-355. Our 8L90 and 8L45 solenoid guide has the full solenoid table, and the valve body testing guide covers the bore wear side.
No year range is attached to this remanufactured listing, so treat 24272280 as the deciding factor. The same number serves the 8L90, and the listing references the Cadillac CT6 among other GM applications. Pull the number from your old solenoid and compare the connector, or send us the year and VIN and we will confirm it before it ships. If you would rather install a new unit on a 2017-or-later truck, the new 2017-up 8L45 TCC solenoid is the alternative. The full lineup is on our 8-speed parts page.
Drain the fluid, drop the pan and work on the control valve body. Label every connector before unplugging; the TCC and S4 solenoids sit side by side with compatible plugs, and swapping them causes a neutral on the 1-2 shift. Fit a fresh O-ring, and if the solenoid has a screen, make sure it is clean and seated. While the pan is off, check the internal harness connectors and conduit for cracks or rubbed wires, since a harness fault can set the same codes as a bad solenoid; a replacement is listed as the 8L45 internal wiring harness. Refill with a DEXRON HP licensed fluid such as Mobil 1 LV ATF HP, then have the solenoid characterization loaded to the TCM through GM service programming. A short highway drive with several lockup and release cycles confirms the repair.
| Fits | 8L45 |
| Part type | Tcc Solenoid |
| Condition | Remanufactured |
| Brand | OEM |
| Reference | 24272280 |
| Ships | From the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
This unit is remanufactured and tested before it ships. It is the lower-cost option; if you prefer new, we also list a new 2017-up 8L45 version with the same reference number.
The 8L45 is GM's lighter-duty 8-speed, used in applications such as the Colorado, Canyon, Camaro and Cadillac cars including the CT6. Always confirm by part number or VIN.
The solenoid is serviced at the control valve body under the pan. Follow the factory procedure for your VIN, and keep track of connector positions so the TCC and S4 plugs are not swapped.
Usually not. A code-free shudder at steady cruise is the condition in GM bulletin 18-NA-355, fixed by a complete exchange to Mobil 1 LV ATF HP. Replace the solenoid when there is a TCC code or a bad resistance reading.
