6L45 Shift Kit, new and ready to install. Fits the 6L45. Ships fast from the USA.
If your 6L45 has started flaring between gears, slamming the converter clutch on, running hot, or setting P0731, P0751 or P0776 after a valve body has already been swapped once, the problem is usually pressure leaking out of worn bores rather than a dead solenoid. This listing is the Sonnax 6L45-6L90-MINI shift and TCC kit, a drop-in valve body repair package for the light-duty 6L45 (GM RPO MYA, and the GA6L45R BMW installed) that also covers the 6L50, 6L80 and 6L90 because the whole family shares the same valve body design.
The 6L45 has no shift valves in the old sense. Its control module bolts to the valve body and drives solenoids that meter oil to five clutches, so every apply depends on line pressure, actuator feed pressure and clutch regulator pressure staying where the module expects them. After high mileage the main line, solenoid feed and lockup circuits all leak at worn valve bores, and the module compensates until it runs out of adapt range. Sonnax built this kit around those exact circuits: a replacement pressure regulator valve, a line pressure booster kit, an actuator feed limit valve kit and a TCC regulator valve kit, all designed to drop into the original bores with no reaming and no special tools.
The second half of the kit is what sets it apart. The control module carries pressure switches that tell it when a clutch circuit is filled. Sonnax explains in its pressure switch tech article that those switches are used both for gear selection and clutch timing, so one that sticks or leaks causes wrong-gear and timing complaints. This kit includes laminate discs, seals and an installation tool kit to rebuild the switch assembly, plus a set of check balls, so a failed switch does not automatically mean buying a new module.
Pull codes and freeze frame data first, and check fluid level hot. A 6L45 that will not move at all needs a different first test: Sonnax documents that a line pressure solenoid stuck in exhaust gives a flat 60-68 psi reading, which is a solenoid or wiring problem, not bore wear. Our 6L45 limp mode guide walks through separating electrical faults from hydraulic ones, and the valve body testing guide covers vacuum testing the bores this kit targets. If the clutch packs are burnt, the kit alone will not save the unit.
The kit is catalogued for the 6L45, 6L50, 6L80 and 6L90. That covers the 6L45 in GM cars and the GA6L45R in BMW models. Upper valve bodies are unique by RPO across the family, so the kit's parts go back into your original valve body rather than turning one model into another. Before ordering, confirm the transmission is a 6L45 by the RPO on the build sticker or the tag on the case, or send us your year and VIN and we will check it. Browse the full 6L45 parts collection for matching parts.
| Fits | 6L45 |
| Part type | Shift Kit |
| Condition | New |
| Brand | Sonnax |
| Ships | From the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
Yes. The Sonnax 6L45-6L90-MINI is built for the whole family: 6L45, 6L50, 6L80 and 6L90. The parts go into your existing valve body, so you still need the correct valve body for your RPO.
Not by itself in most cases. A no-movement complaint is often a line pressure solenoid stuck in exhaust or a failed 1-2-3-4 clutch circuit. Read your line pressure first; if it sits flat around 60-68 psi, diagnose the solenoid and wiring before installing a shift kit.
Often. The kit includes the discs, seals and tools to rebuild the pressure switch assembly, which is a common reason the module gets replaced. If the module has an internal electronic fault, it still needs replacing or reprogramming.
Sonnax lists P0731, P0751 and P0776 along with pressure control out-of-range codes, harsh TCC apply, low line pressure and slips, flares and bind-ups.
Refill with Dexron VI, set the level hot through the fill check plug, then clear the transmission adapts with a capable scan tool and drive the vehicle through all gears so the module relearns.
No. The valves in this kit are drop-in parts made to seal worn bores without reaming or special tools. A badly scored bore may still need a replacement valve body.
