Hybrid Direct, 2-3-4 Clutch Releases

WARNING: This page is about a different car, the 2012 GMC Yukon, 2012 Chevrolet Tahoe, and 2012 Cadillac Escalade. However, it is still accessible from the selected car via links, so may be relevant.

If the transmission is operating in Second gear when an electrical malfunction occurs, the shift solenoid 1 defaults to its normally closed state (OFF) and the hybrid direct, 2-3-4 clutch is released.

Shift Solenoid 1

The shift solenoid 1 defaults to its normally closed state (OFF), allowing solenoid 1 signal fluid to exhaust from the shift solenoid valve - mode A, the hybrid direct, 2-3-4 clutch regulator valve, and the 1-3 clutch regulator valve.

Hybrid Direct, 2-3-4 Clutch Assembly

HD 234 clutch fluid pressure is exhausted from the rear case assembly, allowing hybrid direct, 2-3-4 clutch spring force to move the hybrid direct, 2-3-4 clutch piston and release the hybrid direct, 2-3-4 clutch plates.

Shift Solenoid Valve - Mode B

Exhausting HD 234 clutch fluid pressure passes through the shift solenoid valve - mode B into the HD 234 clutch supply circuit.

Shift Solenoid Valve - Mode A

Shift solenoid valve - mode A spring force moves the shift solenoid valve - mode A to the released position, allowing HD 234 clutch supply fluid pressure to exhaust through the valve into the backfill circuit.

Clutch Piston Exhaust Blowoff Ball Valve

Excess fluid pressure in the backfill circuit exhausts at the clutch piston exhaust blowoff ball valve in order to maintain a constant backfill fluid pressure of 2 psi.