8L45 Tcc Solenoid 2017, new and ready to install. Fits the 8L45. Ships fast from the USA.
If the 8-speed in your 2017-or-newer Colorado, Canyon, Camaro or Cadillac will not lock the converter at highway speed, the tach sits a few hundred RPM higher than it used to, or the scan tool shows P0741, the torque converter clutch solenoid is one of the first parts to check. This is a new TCC lockup solenoid that interchanges with GM part number 24272280, listed for 2017-and-later 8L45 transmissions.
GM's 8-speed family uses nine solenoids on the control valve body. Seven are variable force pressure control solenoids and two are simple on/off units. The TCC solenoid sits in the S7 position, and it is a normally low design: with no current from the TCM it sends little or no signal pressure, so the converter clutch stays released. As the TCM raises current, signal pressure climbs, strokes the clutch control valve in the S7 bore and feeds apply oil to the converter clutch. That variable control is what lets the computer slip the clutch gently at light cruise instead of slamming it on, and it is also why a solenoid that has drifted out of calibration shows up as shudder or slip long before it fails outright.
Rule out the fluid first. GM bulletin 18-NA-355 covers a rumble-strip shudder at 25-80 mph on this whole 8-speed family, and the factory fix is a complete fluid exchange to Mobil 1 Synthetic LV ATF HP, not a solenoid. If the shudder came back after that exchange, or you have a hard lockup code, check the S7 circuit: all of the pressure control solenoids in this unit should measure 4.5-5.5 ohms. A healthy reading does not clear the hydraulics, though. Sonnax has documented that the wrong clutch control valve in the S7 bore causes no TCC apply or high slip with P2808, which looks exactly like a dead solenoid. Our 8L90 and 8L45 common problems guide walks through separating fluid, bore wear and solenoid faults.
This version is listed for 2017-and-later 8L45 units and carries reference number 24272280; the same part number is also used in the 8L90. GM revised parts of this valve body over the years, and some 2019-up units changed the neighboring S4 circuit, so compare the number and connector on the solenoid you remove, or send us your year and VIN before ordering. If your truck is a 2015-2016 build, look at the 8L45 TCC solenoid listing and confirm the number. Every 8-speed part we carry is on the 8L90 and 8L45 parts page.
The solenoid is serviced from under the pan on the control valve body. Note which position each connector came from: Sonnax warns that swapping the S4 and TCC solenoids produces a neutral on the 1-2 shift, and the two share compatible connectors, so it is an easy mistake. Install a new O-ring, keep the bore and screen clean, and inspect the S7 clutch control valve and its signal accumulator for wear while you are in there. If the bores are scored, a valve body shudder fix kit addresses the circuit rather than just the solenoid. Refill only with DEXRON HP licensed fluid such as Mobil 1 LV ATF HP. GEARS Magazine notes that each solenoid carries a part unique number, and after replacing solenoids the characterization data should be downloaded to the TCM through GM service programming so the computer knows how this solenoid behaves. Finish with several lockup cycles on the highway and confirm slip RPM stays near zero once applied.
| Fits | 8L45 2017 |
| Part type | Tcc Solenoid |
| Condition | New |
| 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.
The reference number 24272280 is shared by the 8L45 and 8L90, and the listing calls out both units. Match the number on your old solenoid or send us your VIN to be sure.
Only if the solenoid is the cause. Most cruise shudder on this family is covered by GM bulletin 18-NA-355 and is fixed with a full Mobil 1 LV ATF HP exchange. Replace the solenoid when there is a TCC code or the shudder persists after the fluid exchange.
GEARS Magazine lists 4.5-5.5 ohms for the pressure control solenoids in this transmission, including the TCC solenoid.
Each solenoid has a part unique number, and GM's procedure is to download the characterization data to the TCM after replacing solenoids. Without it the unit may run but shift and lockup quality can suffer.
A DEXRON HP licensed fluid such as Mobil 1 Synthetic LV ATF HP. Do not top off with older DEXRON VI.
