Function of automotive transmission system components
The "transmission system" of a car is usually referred to as the "transmission" system. Its core function is to efficiently and smoothly transfer the power output by the engine to the driving wheels, enabling the vehicle to move. According to authoritative public information, the components and functions of the transmission system are as follows:
Components and functions of the transmission system
Clutch: Connects or disconnects the power transmission between the engine and the gearbox, enabling smooth starting and smooth gear shifting; it can also interrupt the power transmission when necessary to prevent overload of the transmission system.
Transmission (gearbox): Changes the output speed and torque through different gear ratios to adapt to different driving conditions (such as acceleration, climbing, and high-speed cruising); it also allows reverse gear and disengages power when in neutral.
Universal drive device (including universal joints and transmission shafts): Transmits power between two shafts with changing axial angles or relative positions, especially suitable for rear-wheel drive or four-wheel drive vehicles for connecting the gearbox and the drive axle.
Main reducer: Reduces speed, increases torque, and changes the direction of power transmission by 90° (usually from longitudinal to lateral), then transmits it to the differential.
Differential: Allows the left and right (or front and rear) driving wheels to rotate at different speeds to prevent tire slipping or wear during turning.
Drive shaft (driving shaft): Directly transmits the power output from the differential to the driving wheels to drive the vehicle forward.
Summary of the core functions of the transmission system
Speed reduction and torque increase: The main reducer enhances the torque of the driving wheels to meet the requirements of starting and climbing.
Speed change and torque change: The transmission adapts to different speeds and loads through different gear ratios.
Reverse gear: Utilizes the reverse gear of the transmission to achieve reverse driving.
Interrupt power transmission: Facilitates gear shifting, parking, or idling by cutting off power transmission.
Differential effect: Ensures the difference in rotational speeds between the inner and outer wheels during turning, improving handling stability.
Note: Different driving configurations (such as front-wheel drive, front-engine rear-wheel drive, or four-wheel drive) will affect the specific structure. For example, front-wheel drive vehicles usually omit the transmission shaft, while four-wheel drive vehicles will add a transfer case.
The "transmission system" of a car is usually referred to as the "transmission" system (Transmission System), responsible for transferring the power output by the engine to the driving wheels. If there is an assembly component failure, it is necessary to determine the cause based on specific symptoms and the vehicle model. The following are general solutions based on authoritative public information:
Common fault causes and corresponding solutions
Clutch slipping
Symptom: Weak acceleration, burnt smell, increased engine speed but no increase in vehicle speed
Solution: Adjust the free travel of the clutch pedal, or replace the friction plate, pressure plate, etc.
Transmission malfunction (such as gear shifting issues, abnormal noise, difficulty shifting gears)
Symptom: Automatic shift to neutral after engaging gears, shifting jolts, gear impact sounds
Solution: Check the wear of gears, splines, synchronizers, and replace related components and tighten the stop mechanism
Transmission shaft/Universal joint problems
Symptom: "Clack" noise during driving, vehicle body shaking
Solution: Check the balance of the universal joint and transmission shaft, replace worn bearings or redo the dynamic balance
Hydraulic system malfunction (common in automatic transmissions)
Symptom: Insufficient oil pressure, delayed shifting, high temperature
Solution: Measure the pressure at the pressure points, compare with standard values; check the throttle valve, reversing valve; if necessary, replace the transmission oil or repair the internal valve body
Electronic control system failure (ECU, sensor false alarms)
Symptom: Fault light on but no obvious mechanical abnormalities
Solution: Try to "shut off the engine and lock the vehicle for 5 minutes and restart" first. If the fault disappears, it is a program error; if it persists, use a diagnostic tool to read the fault code and handle it specifically
Carbon buildup or fuel system affecting power transmission
Symptom: Idle vibration, acceleration delay, intermittent triggering of the transmission system alarm
Solution: Clean the fuel injectors, intake air passage of carbon deposits, replace spark plugs or ignition coils Suggested Operating Procedure
Immediate Parking Check: If accompanied by severe abnormal noise, complete loss of power, or smoke emission, immediately pull over and shut off the engine.
Attempt Restart: After leaving the vehicle for 5 minutes with the engine off, restart it to rule out temporary electronic faults.
Observe Basic Condition: Check for obvious oil leakage, slack transmission belt, or specific fault codes on the dashboard.
Avoid Self-Dismantling: The transmission system involves precise machinery and electronic control. It is not recommended for non-professionals to repair it.
Go to Professional Institution: It is recommended to visit the brand's authorized service center (such as a BMW 4S store) or a qualified repair shop, using specialized diagnostic equipment to accurately locate the fault.
Note: Different vehicle models (such as front-wheel drive, rear-wheel drive, or four-wheel drive) have significant differences in transmission structures. The repair plan needs to be combined with the specific model. For example, most BMWs are front-wheel drive, and the power transmission path is longer. Any failure in any part (clutch, gearbox, transmission shaft, differential) may trigger the "Transmission System Failure" prompt.
If further diagnosis is needed, provide the specific model, fault code (such as P0700), or abnormal phenomena (such as the type of abnormal noise, whether accompanied by warning lights), so as to conduct a more precise analysis.
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