E. Third Range Operation

The converter flow valve is stroked, exhausting converter-in pressure to sump, and eliminating the separating force between the TCC piston and the converter cover. At the same time, the converter flow valve opens the passage supplying TCC-apply pressure to the converter-out circuit. The pressure differential across the TCC piston applies the torque converter clutch.

• Depending upon the calibration, TCC solenoid could be energized in ranges 2–6.

The calibrations can also apply the TCC for special applications such as PTO operation controlled directly by engine speed with transmission in neutral or TCC operation in first hold.

E. Hydraulic Circuit—Third Range (Foldout 7) • Before making the shift from second to third range, the TCM makes certain all of the shift valves are in the correct position with SV1, SV2, and SV3 de-stroked. • PCS2 is de-energized, exhausting PCS2 signal pressure which allows PCV2 to de-stroke, exhausting C4 Clutch. PCS1 is de-energized, raising PCS1 signal and PCS1 pressures. The PCS1 pressure is directed through SV2 to C3 clutch. The TCM reduces current to PCS1, which controls the rate at which PCV1 supplies pressure to C3 clutch, and reduces current to PCS2, which controls the rate at which PCV2 exhaust C4 clutch, assuring a smooth transition to third range. Main pressure continues to flow through SS3 and Manual Selector valve to C1 clutch, keeping the clutch applied. • The combination of C1 and C3 clutch application produces third range operation. • After the shift into third range is complete, SS1 is energized and directs control main pressure to the top of SV1, stroking the valve. With SV1 in its stroked position, C4 clutch feed is exhausted through SV1 to exhaust backfill keeping the C4 clutch released and C2 clutch has an exhaust path through SV1 to PCV2, keeping the C2 clutch released. • PS1 turns on, providing feedback that SV1 is stroked. PS2 and PS3 remain off, providing feedback that SV2 and SV3 are in their destroked position. • If electrical power is interrupted while the transmission is in third range, SS1 and the

TCC solenoid (if TCC is applied) are deenergized. SV1 de-strokes, changing the exhaust path of C2 clutch to exhaust backfill and the exhaust path of C4 clutch to the

PCV2. Normally closed PCS1 continues to block the exhaust of the PCS1 signal pressure (signal remains control main). The signal pressure on top of PCV1 produces maximum

PCS1 pressure, which is routed through SV2 to C3 clutch, keeping the clutch applied. With the Manual Selector Valve in a forward position, main pressure continues to feed C1 clutch through SV3 and the Manual Selector

Valve. The combination of C1 and C3 clutches applied keeps the transmission in third range for limp home capability. If the TCC is applied, the TCC solenoid de-energizes, causing the TCC valve to de-stroke, exhausting pressure from the top of the converter flow valve. The converter flow valve de-strokes, redirecting main overage to converter in and converter out to the cooler.

The TCC is now released.

• If electrical power is interrupted while the transmission is in third range, and the Manual

Selector Valve is moved to neutral, C1 clutch exhausts through the Manual Selector Valve to exhaust backfill. C3 clutch remains applied.

With only one clutch applied, the transmission goes to neutral (refer to paragraph A—

Neutral).

• If electrical power is interrupted while the transmission is in third range and the Manual

Selector Valve is moved to the reverse position, C1 exhausts through the manual

Selector Valve which releases the clutch. Main pressure goes through SV3, the Manual

Selector Valve and SV2 to C5 clutch, applying the clutch. The combination of C3 and C5 clutch application produces reverse range for limp home capability.