Automatic gearbox - ZF4HP22/24 (Gear ratios): Description and operation

Intermediate plate The intermediate plate supports the gearbox input shaft and provides the interface between the transmission fluid pump and the lubrication circuit. The pump attaches to the front of the intermediate plate and is driven by the impeller in the torque converter. The pump pressurises transmission fluid drawn from the sump on the gearbox housing. The pressurised fluid then circulates through the torque converter and gearbox housing components for cooling, lubrication and gear shift purposes. Ports around the outer periphery of the intermediate plate provide the inlet and outlet connections to the fluid cooler and a pressure take-off point for servicing.

Gearbox housing The gearbox housing contains two epicyclic gear sets on input and output shafts. Hydraulic brake clutches on the shafts, control which elements of the gear sets are engaged, and their direction of rotation, to produce the P and N selections, four forward gear ratios and one reverse gear ratio.

Gear ratios