Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
General and components: Components
The transmission's mechanical components are enclosed in the torque converter housing (1), the transmission housing (2), with integrated final drive housing (3) and in the 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 acted on by the gear shift linkage rod are, like other electric components, connected to a connector (9).
The gear-shift position sensor, which informs the control module the gear that 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. Lock-up solenoid SL regulates the torque converter lock-up function. Both the gear shift solenoids S1 and S2 control shifting. These valves are activated by the transmission control module (TCM), as is the line pressure solenoid valve STH, that 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 vehicle speed sensor (VSS) (7) is activated by a toothed impulse wheel. The sensor sends vehicle speed status signals to the transmission control module (TCM).
An NTC type temperature sensor (6) measures the oil temperature. The control module receives this information and uses it to calculate gear 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 also occurs at approximately 115° C. This reduces slippage and therefore heat generation in the transmission.
The gear-shift position sensor has three separate functions:
- Transmitting an electronic signal to inform the control module which gear has been selected.
- Operating the back-up (reversing) lamp when the gear selector is in position R.
- Preventing the engine from being started unless the gear selector is in the P or N positions.
The transmission and final drive share a common oil pan. A dipstick in the engine compartment is used to check the transmission oil.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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