Overdrive Clutch Assembly. Description and Operation

Overdrive (O/D) (4, 5, 6) Clutch, Exploded View

Overdrive (O/D) (4, 5, 6) Clutch, Sectional View

Overdrive Clutch Mechanical Operation

The overdrive clutch is a driving clutch that transmits power from the direct/overdrive clutch hub assembly to the rear planetary carrier. The overdrive clutch is applied in 4th, 5th and 6th gears.

Hydraulic pressure from the regulator valve in the valve body pushes the overdrive clutch piston against the overdrive clutch pack to apply the clutch. The input shaft and direct/overdrive clutch hub assembly transmit torque to the rear planetary carrier when the clutch is applied.

Overdrive Clutch (4, 5, 6) Hydraulic Circuits (Applied in 4th, 5th and 6th Gears)

Line pressure is supplied to the Low Reverse/456 Regulator Valve by the pump in every gear and in any manual lever position. To apply the Low/Reverse clutch, the SSD solenoid pressure varies the Low Reverse/456 Regulator Valve and the shuttle valves. As the regulator valve moves, it supplies the Clutch Apply Bypass Valve and the Low Reverse/456 Shuttle Valve with regulated line pressure through the CBR1/C456 circuit. The Low Reverse/456 Shuttle Valve directs regulated line pressure to the opposite side of the Low Reverse/456 Regulator Valve through the CBR1/C456 FDBK circuit to gradually overlap (4, 5, 6) clutch apply.

To apply the Overdrive (4, 5, 6) clutch, the clutch apply bypass valve spool position regulates line pressure into the CBR1/C456 circuit, supplying the C456 circuit and applying the Overdrive (4, 5, 6) clutch. The Clutch Apply Bypass Valve latch pressure is supplied to the C456 circuit. The Overdrive (4, 5, 6) clutch is applied in 4th, 5th and 6th gears.

Overdrive (4, 5, 6) Clutch Hydraulic Circuits (Released)

When the Overdrive (4, 5, 6) clutch is released in 1st gear above 8 km/h, in 2nd and 3rd gears the SSD solenoid pressure is removed from the Low Reverse/456 Regulator Valve and shuttle valves, which position the valves to block line pressure and release the Overdrive (4, 5, 6) clutch.

When the Overdrive (4, 5, 6) clutch is released in 1st gear above 8 km/h, in 2nd and 3rd gears exhaust is supplied to the Low Reverse/456 Clutch Regulator Valve and the Clutch Apply Bypass Valve by the manual valve through the DR DV circuit, which directs fluid to the Low Reverse Blocking Valve. The Low/Reverse clutch and the Overdrive (4, 5, 6) clutch fill the unused circuits with unpressurized transmission fluid.

When the Overdrive (4, 5, 6) clutch is released in PARK, REVERSE, NEUTRAL and 1st gear below 8 km/h, the Low Reverse/456 Regulator Valve supplies regulated pressure to the Clutch Apply Bypass Valve through the CBR1/C456 circuit. When the ON/OFF SSE is in the ON position, regulated pressure is directed to the Low/Reverse clutch.

For detailed information on valve body hydraulic circuits and solenoid operation, refer to
For additional information, refer to: Transmission Description - System Operation and Component Description (307-01A Automatic Transmission - 6-Speed Automatic Transmission - 6F35, Description and Operation).

Overdrive (4, 5, 6) Clutch Fluid Passages