Automatic gearbox - JF403E (Hydraulic Clutches): Description and operation

Hydraulic Clutches

The transmission employs 4 clutches and 1 reverse brake. The number of driven and intermediate plates vary in each clutch hub depending on the clutches function.

Each clutch also incorporates a dished spring ring to reduce shock when the clutch is engaged. The clutch is operated by a hydraulic piston incorporating a reed or check valve, this prevents pressure build up within the clutch when the clutch is disengaged.

Forward clutch

The forward clutch comprises 5 driven plates and 6 intermediate plates. The clutch is engaged in all forward gears.

Over-run clutch

The over-run clutch comprises 5 driven plates and 6 intermediate plates and is located within the forward clutch drum. Operation of the clutch the controlled by the ECM via the over-run clutch solenoid and over-run clutch control valve.

Reverse clutch

The reverse clutch comprises 2 driven plates and 3 intermediate plates, with a machined outer surface on the clutch drum for the brake band. The reverse clutch only engages in reverse gear.

High clutch

The high clutch comprises 4 driven plates and 5 intermediate plates, with the clutch drum being an integral part of the input shaft. The high clutch engages in 3rd and 4th gears.

Low and Reverse brake

The low and reverse clutch comprises 7 driven plates and 8 intermediate plates and engages in reverse gear, and 1st gear when ’1’ is selected.