Transmission Oil: The “Blood” of Automobile Transmission
The transmission, as the core component of the automobile transmission system, undertakes the important responsibilities of speed change and torque conversion. Its internal structure is complex, consisting of numerous precision gears, friction plates and other components. When the vehicle is in motion, the transmission oil plays multiple key roles. It not only lubricates to reduce friction and wear between components but also has the functions of heat dissipation, power transmission and cleaning. Take the commonly seen AT automatic transmission in family cars as an example. The internal torque converter relies on the transmission oil to transmit power, and the transmission shift valve body also needs to be controlled by the transmission oil.Degraded Transmission Oil: The Source of Vehicle Hazards
With the increase of usage time and the accumulation of driving mileage, the transmission oil will gradually deteriorate. After the transmission oil deteriorates, its lubricating performance drops significantly, which will lead to increased wear of gears and other components and raise the probability of failures. Specifically, it will not only affect the smoothness of gear shifting, greatly reducing the driving experience, but may also trigger more serious mechanical failures, resulting in a substantial increase in maintenance costs. According to reports from the Automatic Transmission Service Group (ATSG) in the United States, on average, 13 million automatic transmissions fail in the United States every year, and more than 90% of these failures are caused by untimely oil changes. In terms of failure phenomena, there may be transmission jitters, inability to shift gears, displacement, and even breakage of gears and bearings; it may also cause the transmission to overheat, leading to deformation and melting of O-rings, gaskets, rubber rings and sealing parts due to overheating; or it may cause blockage inside the transmission, resulting in the failure of the transmission’s sealing performance. In the case of manual transmissions, there may be situations such as failure to shift gears or gear displacement.Accurately Grasp the Oil Change Cycle
Generally, the vehicle’s user manual will clearly state the recommended oil change cycle for the transmission, usually every 40,000 to 60,000 kilometers or every 2 to 3 years. However, the actual oil change cycle cannot be generalized and needs to be adjusted flexibly according to the vehicle’s usage conditions. For example, vehicles that often drive in congested traffic conditions, frequently start and stop, or are used for special working conditions such as towing and heavy loading should appropriately shorten the oil change cycle. Different transmission brands also have different oil change cycles for their transmission oils. For most automatic transmission oils, the oil change cycle is mostly every 2 to 3 years or every 40,000 to 60,000 kilometers, while manual transmission oil generally needs to be replaced every 60,000 to 80,000 kilometers.In-depth Analysis of Two Mainstream Oil Change Methods
Gravity Oil Change: This is a more traditional method. By unscrewing the oil drain bolt at the bottom of the transmission, the old oil flows out naturally under the action of gravity. Its advantage lies in its simplicity of operation and low cost. However, its disadvantages are also obvious. The oil change is not thorough enough, and only about 40% to 60% of the old oil can be replaced. The reason is that there are many oil passages and hard-to-reach corners inside the transmission, and it is difficult for the old oil to flow out completely relying on gravity.
Circulating Machine Oil Change: Using the pressure generated by the machine, new oil is continuously injected into the transmission while the old oil is replaced in an equal amount. This method can replace the transmission oil more thoroughly, with an oil change rate of 80% to 95%. However, the circulating machine oil change requires a larger amount of new oil, resulting in relatively higher costs. Moreover, it has stricter requirements for the equipment and operators.
Key Points That Cannot Be Ignored Before and After the Oil Change
Preparation Before the Oil Change
- Determine the Oil Change Cycle: Refer to the vehicle maintenance manual and combine it with the actual driving mileage and the condition of the oil to determine the best time for the oil change.
- Select the Appropriate Transmission Oil: Strictly follow the vehicle model and the manufacturer’s recommendation to select the suitable transmission oil. For continuously variable transmissions (AT) and automatic transmission models, it is recommended to use oil of grade 4A or 5W-40; for manual transmission models, it is recommended to use oil of grade M/T or SAE75W.
- Make an Appointment with a Maintenance Shop: To ensure a smooth oil change process, it is recommended to make an appointment with a professional auto maintenance shop in advance.
Oil Change Process
- Stop the Vehicle and Turn Off the Engine: Turn off the engine and engage the parking brake to prevent the vehicle from sliding during the oil change process.
- Remove the Oil Pan Screw: Locate the oil pan screw of the vehicle and use a wrench to remove it to drain the original transmission oil.
- Extract the Old Oil: Use a waste plastic pipe or funnel to extract the old oil from the bottom of the transmission until the oil is clear. This step can effectively reduce the impact of impurities and moisture in the old oil on the new oil.
- Clean the Transmission: Use a special cleaner to clean the inside of the transmission to ensure that there is no residual old oil.
- Replace the Filter: Remove the old filter, replace it with a new one, and ensure that the new filter is well sealed.
- Inject New Oil: Pour the new oil into the transmission, making sure not to exceed the maximum mark line. Then start the engine and let it idle for 5 to 10 minutes to allow the new oil to fully lubricate all parts.
- Install the Oil Pan Screw: After the engine cools down, reinstall the oil pan screw and tighten the nut.
- Check the Oil Level: After starting the engine, turn on the turn signal and observe whether the oil level indicator light on the dashboard flashes normally. If it flashes, it means that the new oil has been successfully added.
Inspection After the Oil Change
- Check for System Leaks: Carefully check the external and internal pipelines to ensure that there is no leakage. If there is a leak, it needs to be dealt with in a timely manner.
- Start and Check: Start the engine and check whether the transmission is working properly and whether there are any abnormal noises or vibrations.
Transmission oil change is an important item in car maintenance that cannot be underestimated. Regular and correct replacement of transmission oil can keep your beloved car in good performance, extend its service life, and provide a safeguard for your travels. Do not cause unnecessary damage to the vehicle due to momentary negligence. Paying attention to transmission oil change means paying attention to your own driving experience and driving safety.
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