How to Change Transmission Oil with a Flushing Machine?
3 Answers
Steps for changing transmission oil with a flushing machine: 1. First, locate the vehicle's external flushing machine connector. After finding the connector, identify the inlet or outlet hose. 2. Then, connect the flushing machine's hoses to the machine, fill the container with automatic transmission fluid, and proceed with the oil change (Note: During the process, carefully monitor the hoses for any leaks). 3. Typically, using a flushing machine for transmission oil change requires more than double the amount of new oil compared to manual replacement, approximately 9-12 liters. Although the cost is higher, the results are significantly better, making this method suitable for automatic transmissions.
I have experience with transmission fluid changes using a circulation machine. Last time at the repair shop, I observed the entire process, which took about forty minutes: first, the vehicle was lifted, and the inlet and outlet ports were located on the transmission cooling oil lines to connect the two tubes of the circulation machine. Then, the engine was started to allow the transmission fluid to circulate under the machine's pressure. While new fluid was pumped into the transmission from the machine, the old fluid was extracted into the machine's waste bucket. The technician told me it's crucial to ensure the new fluid's specifications exactly match the manufacturer's requirements; otherwise, it could damage the solenoid valves. The most noticeable improvement after the change was significantly smoother gear shifts, especially when crawling in traffic without any jerking. This method costs about 300 yuan more than the traditional gravity drain but replaces over 90% of the old fluid, making it particularly suitable for older vehicles with 70,000 to 80,000 kilometers on them. I recommend choosing a reputable chain shop for this service, as their machines offer more precise pressure control.
The transmission fluid exchange via a flushing machine is more thorough compared to traditional methods, as I've compared both approaches. The core procedure involves connecting both ends of the transmission cooling lines to the machine, using hydraulic principles to displace old fluid with new fluid. The critical point is maintaining idle speed when starting the engine, with machine pressure controlled between 20-35 psi - excessive pressure may damage seals. The entire process typically requires about 1.5 times the manufacturer-recommended fluid quantity. For instance, if the manual specifies 6 liters, prepare 9 liters. After the exchange, it's advisable to let the vehicle idle for five minutes before checking the fluid level. This method effectively removes stubborn sludge, extending transmission lifespan by three to five years. While more expensive upfront, it saves costly overhaul expenses later. Always verify the new fluid color matches the old fluid to confirm correct specification.
