Component Descriptions

The transmission's mechanical components are enclosed in the torque converter housing (1), the transmission housing (2), with integrated final drive housing (3) and valve housing cover (4). The transmission speed sensor (5) in the transmission housing, the temperature sensor (6), the Vehicle Speed Sensor (VSS) (7) and the gear-shift position sensor (8), which is affected by the gear selector shaft (control shaft) are, like other electric components, connected to a connector (9). The gearshift position sensor, which informs the control module which gear has been selected, also contains a back-up (reversing) light and a Park/Neutral Position (PNP) switch.

The solenoid valves (SL, S1, S2, STH) are located in the hydraulic system valve housing (control system), which is located beneath the valve housing cover-on the transmission. The lock-up solenoid valve SL regulates the torque converter lock-up function, and shifting valves S1 and S2 control shifting. These valves are activated by the Transmission Control Module (TCM), as is the system pressure solenoid valve STH, which controls the transmission line pressure.

The transmission speed sensor (5) is activated by a toothed impulse wheel. By comparing the engine and transmission speeds, the control module can determine the amount of slippage in the torque converter. The electromagnetic VSS (7) is activated by a toothed impulse wheel. The sensor sends vehicle speed status signals to the TCM.

An NTC type temperature sensor (6) measures the oil temperature. The control module uses this information to calculate shifting and lock-up engagement points (temperature controlled lock-up). The lower limit for temperature activated lock-up is at an oil temperature of 20-30°C. Below this limit there is no lock-up function engagement so the transmission reaches its normal operating temperature faster. An upper limit with enhanced engagement occurs at approx. 115°C. This reduces slippage and thus heat generation in the transmission.

The gear-shift position sensor has three separate functions:

- Transmitting a signal informing the control module which gear has been selected.

- Operating the back-up (reversing) lights when the gear selector is in position R.

- Preventing anyone starting the engine without first selecting position P or N. This signal is also transmitted to the engine management system and is used for drive compensation when the engine is idling.

The transmission and final drive share a common oil pan. A dipstick in the engine compartment is used to check the oil in the transmission.