8L45 Shift Kit, new and ready to install. Fits the 8L45. Ships fast from the USA.
The 8L45 is the lighter-duty member of GM's rear-drive eight-speed family, found in the Colorado and Canyon midsize pickups, the Camaro, and Cadillac sedans such as the ATS, CTS, CT4 and CT6. Owners searching for an 8L45 fix usually describe the same things: a flare on the 2-3 shift, a delayed or harsh engagement, a vibration at cruise that feels like rumble strips, or a converter or overtemp code. TransGo does not make a separate 8L45 kit. Its SK 8L90 SHIFT KIT valve body repair kit is engineered for both the 8L45 and 8L90, and that is the kit sold on this page.
The 8L45 shares its control strategy with the 8L90. Seven variable force solenoids send signal pressure to regulator valves, and those valves set apply pressure for whichever clutch is coming on or letting go. Because shifts are clutch-to-clutch, a small leak at a regulator bore turns straight into a flare or a bump. Sonnax technicians identify the S3 and S4 circuits as the worst wear locations in these valve bodies, and a worn pressure regulator lineup can let line pressure climb far past design. TransGo's answer is a set of new drop-in valves for the pressure regulator and shuttle, the TCC regulator, and the S2, S3 and S4 regulators, plus oversize converter feed limit and AFL valves that seal up worn bores.
A failed solenoid or a wiring fault can mimic a worn valve body, so start with a scan for electrical codes and a resistance check of the solenoids, using the steps in our 8L90/8L45 shift solenoid guide. If the complaint is a cruise-speed shudder, try GM's Mobil 1 LV ATF HP fluid exchange before anything else; our shudder and harsh shift guide walks through it. When the electrical side is clean and the complaint survives a correct fluid service, the valve body regulators are the next suspect.
TransGo rates the kit for every 2015-on 8L45 and 8L90. Pay attention to the S4 regulator valve on your unit: GM switched to a later two-land S4 valve around 2018, and TransGo's instructions say to keep that original valve instead of fitting the kit's replacement. If the S4 bore itself is worn, TransGo sells a separate oversize S4 valve. The 8L45 and 8L90 do not share every hard part, so for anything beyond this kit, match the original part or send us your year and VIN. More parts for this family are on the 8L90/8L45 collection page.
Plan on bench work. The valve body comes out, the upper and lower castings are separated, and TransGo tool kit AFL-G2-TK is needed to ream two bores for the oversize valves. Swap valves one circuit at a time, keep each solenoid in its own bore since they have different flow rates, and reuse the factory retainers. The kit includes small O-rings used only to size the new Teflon sealing rings before the valves go in; they are not seals. Torque the valve body bolts to 71 lb-in. With the pan off, it is the right time to fit a fresh filter and pan gasket kit, and if the clutches are already burned, rebuild the unit with an 8L45 rebuild kit instead of relying on the valve body alone. Fill with a DEXRON HP approved fluid such as Mobil 1 LV ATF HP.
Finish by clearing codes and adapts and running the relearn with a scan tool. TransGo notes the transmission adapts best in ordinary driving with the fuel level between 1/4 and 3/4 of a tank.
| Fits | 8L45 |
| Part type | Shift Kit |
| Condition | New |
| Brand | TransGo |
| Ships | From the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
No. TransGo builds one kit, SK 8L90, for both the 8L45 and the 8L90 from 2015 on. The valve body circuits it repairs are common to both transmissions.
It appears in lighter rear-drive and four-wheel-drive GM products such as the Colorado and Canyon, the Camaro and several Cadillac sedans. Confirm your transmission from the label on the case or the vehicle's build information before ordering.
TransGo tool kit AFL-G2-TK, a reamer and guide set used to open the converter feed limit and AFL bores for the oversize valves. The kit cannot be installed correctly without it.
If the flare comes from worn S3 or S4 regulator circuits or erratic line pressure, yes, that is what the kit targets. If a solenoid has failed electrically or the clutches are burned, those parts need replacing as well.
Use a DEXRON HP approved fluid. GM's own bulletins specify Mobil 1 Synthetic LV ATF HP for these eight-speeds, and mixing in older fluids is a known cause of shudder.
