(Without TCC Applied)

Second Range (Without TCC Applied)





Second Range Hydraulic Schematic

Before shifting from first to second range, the Transmission Control Module (TCM) makes certain the C, D, and E Shift Valves are in the correct position with the C and E shift valves up and the D shift valve down.

A Trim Solenoid is energized, opening the A trim signal pressure to exhaust and allowing the A Trim valve to move up, exhausting C5 clutch pressure. Trim Solenoid B is energized, raising the B trim signal and B Trim pressures. The B trim pressure is directed through the C and E Shift Valves to C4 Clutch. The TCM provides current to B Solenoid, which controls the rate at which Trim Valve B supplies pressure to C4 clutch, and current to A Solenoid, which controls the rate at which C5 clutch is exhausted, assuring a smooth transition to second range. Main pressure continues to feed through the E Shift Valve and manual selector valve, keeping C 1 clutch applied.

The combination of C1 and C4 clutch application produces second range operation.

After the shift to second range is complete, the D solenoid is de-energized allowing the D Shift Valve to move up. C5 clutch feed, which was exhausted through Shift Valve D and the A trim valve, now exhausts through exhaust backfill, keeping C5 clutch released. C3 clutch has an exhaust path through Shift Valve D to the A trim valve, keeping the C3 clutch released.

Pressure switches C, D and E turn off, providing feedback that the valves are in the upward position.

If electrical power is interrupted with the transmission in second range, A and B Trim Solenoids de-energize. The normally open B Trim Solenoid exhausts the B trim signal pressure, allowing the B trim valve to move up, exhausting C4 clutch. Normally closed Trim Solenoid A blocks the exhaust of A trim signal pressure, allowing the A trim signal and A Trim Pressures to rise. Trim Valve A directs full trim pressure through the D shift valve to C3 clutch, applying the clutch. C1 clutch continues to be applied with main pressure through the E Shift Valve and Manual Selector Valve. The combination of C1 and C3 clutches applied produces third range converter operation for limp home capability. If the torque converter clutch was applied during the power interrupt, Solenoid F is de-energized and the transmission returns to converter operation. If electrical power is interrupted with the transmission in second range and subsequent third range operation, moving the Manual Selector Valve to N (Neutral) will cut off main pressure to C1 clutch and the clutch will be exhausted. C3 clutch remains applied. Because only one clutch is applied, the transmission goes to N (Neutral). If electrical power is interrupted with the transmission in second range with subsequent third range operation, moving the manual selector valve to R (Reverse) will cut off main pressure to C1 clutch, exhausting C1 clutch. The manual selector directs main pressure through the F Trim Valve and Shift Valve D to C5 clutch, applying the clutch. C3 clutch remains applied. The combination of C3 and C5 clutch application produces R (Reverse) range operation for limp home capability.