What are the disadvantages of using a circulation machine to change transmission fluid?
4 Answers
The drawback of using a circulation machine to change transmission fluid lies in the increased usage of transmission fluid, leading to higher costs. Below is a related introduction: 1. Traditional manual transmission fluid change method: The traditional manual method only replaces the fluid in the transmission oil pan, leaving some ATF inside the transmission that cannot be removed. After the change, new and old fluids are mixed, resulting in an incomplete replacement that doesn't fully serve the purpose of changing the fluid. 2. Circulation machine transmission fluid change method: Using a circulation machine to replace ATF involves simultaneously extracting old fluid and injecting new fluid, using pressure to push out the old fluid with the new one. This ensures that the transmission is filled with new ATF, which can be visually confirmed on the equipment, achieving a complete replacement effect. Generally, using a circulation machine requires more than double the amount of new fluid compared to the traditional manual method. Although the cost increases, the effect is significantly better. A circulation machine generates pressure to dynamically replace automatic transmission fluid, achieving a replacement rate of over 90%. The operation process is simple but requires equipment support.
I'm very cost-conscious when it comes to car maintenance, and I've found that using a transmission fluid exchange machine is outrageously expensive. A regular gravity drain only costs 50 to 80 RMB—it's simple and quick. But the machine method often starts at 150 RMB, sometimes over 200, and requires a specialized shop with the equipment. Not only is it more expensive, but the risks are high too. If the machine isn’t set up properly, the new and old fluids might not mix cleanly, leading to contamination and reduced lubrication. High-pressure flushing can also stir up sediment inside the transmission, and if it clogs tiny passages or the valve body, the transmission is done for. A friend of mine tried it—spent 300 RMB on a machine flush, only to experience rough shifting a week later and ended up paying thousands more for repairs. So unless the car manual explicitly requires it, I always go with the traditional gravity drain—it’s cheaper and safer, and the money saved can go toward other maintenance. At the end of the day, peace of mind is what matters most.
Having worked on cars for years and often doing DIY repairs, I find the transmission fluid exchange machine technique quite challenging. It's crucial to ensure the machine is clean and the oil pipe connections are tight during operation; otherwise, residual old oil can contaminate the new oil, reducing lubrication effectiveness. Worse yet, deposits in an old transmission can be dispersed under high pressure, potentially getting stuck between clutch plates or in the radiator channels, leading to delayed shifting or overheating. I tried it once myself, and afterward, the transmission developed noticeable noises. Upon disassembly, I found that debris had shifted and clogged the filter. Now, I only trust the gravity drain method—letting the old oil slowly drain out and adding new oil as a buffer—which is much lower risk. Beginners should steer clear of the exchange machine; if things go wrong, repair costs can double. Sticking to simple and safe methods is always better than inviting trouble.
Having driven for over twenty years, I'm most wary of transmission fluid exchanges using a flush machine damaging the car. Especially for older models, the intense flushing is too thorough, potentially removing internal protective coatings and increasing friction wear. The detergents in new fluid also loosen sludge, which can clog small components or valve body orifices. I tried it once on my old car, and soon after experienced acceleration shudder - the mechanic said clogged fluid passages had damaged the shift mechanism. Later switching to the conventional gravity drain method, updating the fluid in batches, the vehicle ran smoothly again. In summary, flush machines offer more risks than benefits - I don't recommend taking the chance when gravity draining provides sufficient maintenance longevity. Vehicle health isn't something to gamble with; choose the safer path.
