Ford Fusion: Automatic Transmission - 6-Speed Automatic Transmission – 6F35 / Low/Reverse Clutch Assembly. Description and Operation

Low/Reverse Clutch Exploded View

Low/Reverse Clutch Cutaway View

Low/Reverse Clutch Mechanical Operation

The low/reverse clutch is a brake clutch that holds the low One-Way Clutch (OWC) which is splined to the rear planetary carrier. The low/reverse clutch is applied in manual LOW, REVERSE and 1st gear up to 8 km/h (5 mph).

Hydraulic pressure from the regulator valve in the valve body pushes the low/reverse clutch piston against the low/reverse clutch pack to apply the clutch. The rear planetary carrier is held stationary to the transmission case as a result of the clutch being applied.

Low/Reverse Clutch Hydraulic Circuits (Applied in REVERSE)

Line pressure is supplied to the low reverse/456 regulator valve by the pump in every gear and manual lever position. To apply the low/reverse clutch, SSD supplies varying solenoid pressure to the low reverse/456 regulator and latch valves. As the low reverse/456 regulator valve moves, it supplies the clutch control bypass valve and low reverse/456 latch valve with regulated line pressure through the CBR1/C456 circuit. The low reverse/456 latch valve directs the regulated line pressure to the opposite side of the 456 regulator valve through the CBR1/C456 FDBK circuit for gradual low reverse/456 clutch engagement. The low/reverse clutch is applied in PARK, REVERSE, NEUTRAL, 1st gear below 8 km/h (5 mph) and manual LOW position.

In REVERSE, both solenoid pressure from ON/OFF SSE and line pressure from the manual valve in the REVERSE circuit apply pressure to the clutch control bypass valve to position it for low/reverse clutch application. Regulated line pressure from the CBR1/C456 circuit is directed to the low/reverse clutch by the clutch control bypass valve through the CBR1 circuit to apply the low/reverse clutch.

Low/Reverse Clutch Hydraulic Circuits (Applied in PARK, NEUTRAL, LOW or 1st gear below 8 km/h [5 mph])

When the low/reverse clutch is applied in PARK, NEUTRAL, LOW or 1st gear below 8 km/h (5 mph), only pressure from ON/OFF SSE, positions the clutch control bypass valve. Line pressure from the REVERSE circuit is not supplied by the manual valve.

Low/Reverse Clutch Hydraulic Circuits (Released)

When the low/reverse clutch is released in 1st gear above 8 km/h (5 mph), 2nd and 3rd gears, solenoid pressure from SSD is removed from the low reverse/456 regulator and latch valves which positions the valves to block line pressure and release the low/reverse clutch. Solenoid pressure from SSE is removed from the clutch control bypass valve to position it to apply the overdrive (4, 5, 6) clutch.

When the low/reverse clutch is released in 1st gear above 8 km/h (5 mph), 2nd and 3rd gears, exhaust backfill supplied to the low reverse/456 clutch regulator valve and the clutch control bypass valve by the manual valve through the EXH BF circuit is directed to the low reverse/456 latch valve, low/reverse clutch and overdrive (4, 5, 6) clutch to fill the unused circuits with unpressurized transmission fluid.

When the low/reverse clutch is released in 4th, 5th and 6th gears, the low reverse/456 regulator valve supplies regulated pressure to the clutch control bypass valve through the CBR1/C456 circuit. With ON/OFF SSE in the OFF position, the regulated pressure is directed to the overdrive (4, 5, 6) clutch.

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