Forward (1, 2, 3, 4) Clutch Hydraulic Circuits
Line pressure is supplied to the 1234 regulator valve by the manual valve in the DRIVE and LOW position. To apply the forward (1, 2, 3, 4) clutch, SSA supplies varying solenoid pressure to the 1234 regulator and latch valves. As the regulator valve moves, it supplies the forward (1, 2, 3, 4) clutch and 1234 latch valve with regulated line pressure through the C1234 circuit. The 1234 latch valve directs the regulated line pressure to the opposite side of the 1234 regulator valve through the C1234 FDBK circuit for gradual forward (1, 2, 3, 4) clutch engagement. The forward (1, 2, 3, 4) clutch is applied in 1st, 2nd, 3rd and 4th gears and manual LOW position.
When the forward (1, 2, 3, 4) clutch is released in 5th and 6th gears, solenoid pressure from SSA is removed from the 1234 regulator and latch valves which positions the valves to block line pressure and release the forward (1, 2, 3, 4) clutch. When the forward (1, 2, 3, 4) clutch is released in the PARK, REVERSE or NEUTRAL position, line pressure is not supplied to the forward (1, 2, 3, 4) regulator valve.
In the released position, exhaust backfill supplied to the 1234 regulator and latch valves by the manual valve through the EXH BF circuit is directed to the forward (1, 2, 3, 4) clutch to fill the unused circuits with unpressurized transmission fluid.