The front clutch is a multi-plate type which is engaged in all forward ratios.
The clutch operating piston moves within quite a short cylinder machined in the clutch drum.
A diaphragm type spring contacts a fulcrum ring on the piston at its inner circumference while its outer circumference rests against a snap ring located in a groove in the drum.
A relatively thick pressure plate is installed first in the clutch pack so that its fulcrum ring also contacts the diaphragm.
When fluid at line pressure is admitted to the clutch cylinder, the piston apply force is multiplied by the leverage provided by the diaphragm, as it pivots against the pressure plate.
This exerts a greater apply force on the clutch pack than could be provided by the piston alone and ensures the clutch is firmly engaged.
The spring returns the piston to the off position when the fluid is dumped from the apply circuit.
