AUTOMATIC TRANSMISSION – GM LE DESCRIPTION AND OPERATION GM LE Automatic Transmission Control Diagram A = Hardwired D = CAN Bus J = ISO 9141 K Line M44 1755 A J D 13 12 14 15 16 9 1 2 3 4 5 6 7 8 10 11
AUTOMATIC TRANSMISSION – GM 5L40-E DESCRIPTION AND OPERATION 44-1-13 1 Permanent battery supply (A Fuse) 2 Battery supply (A Fuse) 3 Main relay 4 Starter relay 5 Transmission fluid temperature sensor 6 Input speed sensor 7 Output speed sensor 8 Brake switch 9 EAT ECU 10 Inhibitor switch 11 Solenoid valves 12 Engine Control Module (ECM) 13 Instrument pack 14 Diagnostic socket 15 Selector lever switches 16 Shift interlock solenoid
AUTOMATIC TRANSMISSION – GM LE DESCRIPTION AND OPERATION Description General The GM LE transmission is an electronically controlled, five speed unit specifically for use with the Td6 diesel engine. The transmission is manufactured by General Motors (GM) Powertrain in Strasbourg, France. The transmission is controlled by an Electronic Automatic Transmission (EAT) ECU which contains software to provide operation as a semiautomatic 'Steptronic' transmission. This 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. Movement of the selector lever in a lateral position to the + or – positions puts the transmission into electronic manual 'Steptronic' mode. The GM LE transmission has the following features: l Designed to provide maintenance free operation l Transmission fluid is 'fill for life' l The torque converter features a gradual slip lockup feature with electronic control of lockup and smooth transition to the fully locked condition l Torque converter lockup is available in rd, 4th and 5th gears l EAT ECU controls shift program logic l Connected to ECM via the CAN for system communications l Diagnostics available from the EAT ECU via the ISO 9141 K Line l Default mode if major faults occur. The transmission comprises three main castings the bell housing, the main casing and the extension case. These items are bolted together to form the housing for the transmission components. A single piece fluid pan is bolted to the lower face of the main case and secured with screws. The fluid pan is sealed to the main case by a controlled compression gasket. Removal of the fluid pan allows access to the valve block and solenoids. The fluid pan is fitted with a magnet which collects any metallic particles present in the fluid. The fluid pan also houses a fluid filter which is non-serviceable. If the transmission fluid becomes contaminated or after any procedure requiring the fluid to be drained, the filter must be replaced. The bell housing provides protection for the torque converter. The torque converter is a complete assembly which also contains the variable control lockup clutch. The torque converter also drives a vane type fluid pump via two drive tangs. The fluid pump is located in the bell housing, behind the fluid pump cover. The fluid pump cover and the bell housing are bolted together. The bell housing and fluid pump cover assembly is bolted to the main casing. The main casing contains the following components: l Input shaft l Output shaft l Valve block and solenoids l Six multiplate drive clutches l Three multiplate brake clutches l Four freewheel, one way, sprag type clutches l A planetary gearset assembly. Draining and refilling the transmission is carried out via a drain plug, located in the sump of the transmission and a refill/level plug located on the left hand side of the transmission. When checking the transmission fluid level the fluid must be between C and C. Only Texaco ETL-7045E Automatic transmission fluid should be used for refilling / topping up the transmission.
AUTOMATIC TRANSMISSION – GM 5L40-E DESCRIPTION AND OPERATION 44-1-15