What are the steps to change car transmission fluid?
4 Answers
The steps to change car transmission fluid are: 1. Remove the drain plug at the bottom of the transmission to drain the old fluid; 2. Remove the inner and outer transmission housing; 3. Remove the transmission fluid filter; 4. Take off the oil pan gasket and clean surrounding contaminants; 5. Wipe the cleaned transmission filter with cotton yarn; 6. Add new fluid after reassembly. Transmissions are divided into manual and automatic types. The functions of transmission fluid are: 1. Maintaining cleanliness of the gear system; 2. Providing lubrication and extending the service life of transmission components; 3. Cooling and sealing. The transmission consists of a gear transmission mechanism and a gear shifting mechanism.
Changing transmission fluid is a technical task that requires safe operation. First, lift the vehicle securely using a hoist—if doing it yourself, remember to use a jack along with safety stands for double protection. Locate the drain plug at the bottom of the transmission and slowly loosen it with a wrench. Prepare a large drain pan beforehand, as the old fluid will be hot and dirty—wearing gloves is advisable. After draining completely, check the transmission pan for metal debris that may need cleaning; some vehicles also require replacing the filter. When adding new fluid, pour it slowly through the fill port at the top using a funnel, being careful not to spill any onto the engine. The trickiest part is measuring the fluid level—some vehicles require checking the inspection hole at a specific temperature while the engine is running. Finally, test-drive the car through all gears for a few minutes. The entire process is far more complex than an oil change, so it’s best left to professionals if you're inexperienced.
I've changed the transmission fluid twice at home, and the steps are actually quite simple. First, park the car on level ground and engage the handbrake, then use a jack to lift the car and secure it with safety stands. Crawl under the car to locate the drain plug with the washer, and make sure the engine is cold before loosening it. It takes about ten minutes for the fluid to drain completely, during which you can check the oil pan for any debris. When reinstalling the cleaned plug, remember to replace the washer to prevent leaks. To add new fluid, locate the fill hole on the transmission—I used a manual pump to push it in until fluid overflowed from the inspection hole. After starting the engine, shift through each gear for a few seconds to circulate the fluid, then turn off the engine and top up a bit more. The key is to buy the correct transmission fluid type and verify the capacity.
I just had the transmission fluid changed at the repair shop. The mechanic first lifted the car, removed the engine undercover to expose the transmission. Then they connected specialized equipment to the pipelines and completely drained out the old fluid - about four liters of dark, dirty oil. Afterwards, they replaced the transmission pan gasket and installed a new filter, then used a circulation machine to pump in the new fluid. Finally, they started the engine to check gear operation across all positions and scanned the transmission data with a computer. The whole process took forty minutes and cost over 800 RMB, but it was worth the peace of mind. They also took the opportunity to inspect and tighten all chassis bolts. The shop recommends automatic transmission vehicles should have fluid changes every 60,000 kilometers for optimal maintenance.
