Fourth Band Applies

WARNING: This page is about a different car, the 2007 Cadillac DTS. However, it is still accessible from the selected car via links, so may be relevant.

Manual Valve

Line pressure at the valve enters the D21 fluid circuit which is then routed to the 2-3 shift valve.

2-3 Shift Solenoid (SS) Valve

The 2-3 SS valve de-energizes (turns OFF) in order to allow fluid from the 2-3 SS valve to exhaust through the solenoid. In the absence of 2-3 SS valve fluid pressure at the 2-3 shift valve, spring force acting on the end of the valve moves the valve into the downshifted position.

2-3 Shift Valve

Spring force hold the 2-3 shift valve in the downshifted position. D21 fluid passes through the valve and orifice #10, where the fluid enters the orificed D21Y circuit. Orificed D21Y fluid is then routed to the 3-4 shift valve. D21 fluid also passes through orifice #9, where the fluid enters the coast clutch circuit, and the fluid is routed to the 3-4 shift valve. Coast clutch fluid is then directed to the coast clutch piston, and the fluid applies the clutch.

3-4 Shift Valve

Spring force and D321 fluid hold the 3-4 shift valve in the downshifted position. The 3-4 shift valve allows orificed D21Y fluid to enter the fourth band feed circuit. Fourth band feed is then routed to the 1-2 shift valve.

1-2 Shift Valve

Spring force holds the 1-2 shift valve in the upshifted position. The 1-2 shift valve allows fourth band feed fluid to enter the fourth band circuit.

3-4 Accumulator Assembly

Fourth band fluid is routed to the 3-4 accumulator piston. The fluid actuates the piston during the apply of the fourth band assembly.