Multi-Disc Clutches

Multi-disc Clutches: The GA6HP26Z gearbox requires only 5 clutches to engage 6 gears. The clutches are divided into drive clutches and brake clutches. Clutches A, B and E are drive clutches while clutches C and D are brake clutches. The A, B and E drive clutches are "dynamic pressure" balanced.




Dynamic Pressure Balance (Example: Clutch E)

Oil is applied to the clutch piston on both sides to avoid speed dependent pressure reduction in the clutch. This balance is achieved by the pressure plate (9) and the non-pressurized residual oil in the lubricating oil gallery (1) through which the area between the piston and pressure plate is filled with oil. This ensures the clutch disengages and engages exactly in all speed ranges while also improving gearshift comfort.




Free wheel gearshifts (using overrunning clutches) are not used in this transmission. In the GA6HP26Z gearbox, all gearshifts from 1st to 6th gear and from 6th to 1st gear are executed as overlap shifts. The overlap gearshift system saves weight and space. The electrohydraulic gearshift is executed by valves in the valve body that are controlled by pressure regulators. The speed, pressure and torque curves are shown in the illustration below.