AUTOMATIC TRANSMISSION – ZF HP 44-2-10 DESCRIPTION AND OPERATION ZF HP Automatic Transmission Control Diagram A = Hardwired D = CAN Bus J = ISO 9141 K Line M44 1821A A J D 13 12 14 15 16 9 1 2 3 4 5 6 7 8 10 11
AUTOMATIC TRANSMISSION – ZF 5HP24 DESCRIPTION AND OPERATION 44-2-11 1 Permanent battery supply (A Fuse) 2 Main relay 3 Battery supply (A Fusible link) 4 Comfort start relay 5 Temperature sensor 6 Turbine speed sensor 7 Output speed sensor 8 Brake switch 9 Electronic Automatic Transmission (EAT) ECU 10 Inhibitor switch 11 Solenoid valves 12 Engine Control Module (ECM) 13 Instrument pack 14 Diagnostic socket 15 Selector lever range switch 16 Shift interlock solenoid
AUTOMATIC TRANSMISSION – ZF HP 44-2-12 DESCRIPTION AND OPERATION Description General The ZF HP transmission is an electronically controlled, five speed unit for use with the V petrol engine. The transmission is manufactured by ZF Transmissions GmbH in Saarbrücken, Germany. The transmission is controlled by an Electronic Automatic Transmission (EAT) ECU which contains software to provide operation as a semiautomatic 'Steptronic' transmission. The EAT ECU allows the transmission to be operated as a conventional automatic unit by selecting PR, ND on the selector lever. Movement of the selector lever across the gate to the 'MS' position puts the transmission into electronic 'Sport' mode. Further movement of the lever in a lateral position to the + or – position puts the transmission into electronic manual 'Steptronic' mode. The HP transmission has the following features: l Designed to be maintenance free l Transmission fluid is 'fill for life' l The torque converter features a controlled slip feature with electronically regulated control of lockup, creating a smooth transition to the fully locked condition l Shift programs controlled by the EAT ECU l Connected to the ECM via the CAN for communications l Default mode if major faults occur l Diagnostics available from the EAT ECU via the ISO 9141 K Line. The gearbox comprises three main casings the bell housing, the intermediate plate and the main case. These items are bolted together to form the housing for the transmission components. A fluid pan is bolted to the lower face of the main case and is secured with bolts. The fluid pan is sealed to the main case with a gasket. Removal of the fluid pan allows access to the valve block and solenoids and speed sensors. The fluid pan has four magnets located in each corner which collect any metallic particles present in the transmission fluid. A non-serviceable fluid filter is located inside the fluid pan. If the transmission fluid becomes contaminated or after any service work the filter must be replaced. The bell housing provides protection for the torque converter assembly and also provides the attachment for the gearbox to the engine block. The torque converter is a non-serviceable assembly which also contains the lockup clutch mechanism. The torque converter drives a crescent type pump via drive tangs. The fluid pump is located in the intermediate plate, between the bell housing and the main case. The main case contains the following components: l Input shaft l Output shaft l Valve block and solenoids l Three rotating multiplate drive clutches l Three fixed multiplate brake clutches l One freewheel, one way, sprag type clutch l A planetary gear train comprising three planetary gear sets.
AUTOMATIC TRANSMISSION – ZF 5HP24 DESCRIPTION AND OPERATION 44-2-13