Is the Transmission Prone to Water Ingress?
3 Answers
The transmission can indeed take in water. Regardless of the vehicle model, automatic transmissions are equipped with a radiator. The radiator is designed such that oil flows on one side and water on the other, normally without interference. However, over time, the water side can gradually corrode due to scale buildup. Once the corrosion reaches the oil side, water can enter the transmission. Solutions for water ingress in the transmission: 1. Clean water ingress: Avoid driving or running the engine as much as possible. In this case, water will settle at the bottom of the gear oil in the transmission. Open the drain screw at the bottom of the transmission to release all water and oil, then add new gear oil. 2. Dirty or muddy water ingress: If the vehicle is driven or the engine is run after clean water ingress, the water and oil will be churned at high speed inside the transmission, leading to emulsification. It is difficult to separate oil and water in this state. The transmission must be removed and opened for cleaning. If sand or mud enters the bearings, especially the input shaft bearing, all components inside the transmission must be disassembled and cleaned.
Actually, it's quite difficult for water to get into the transmission. It's designed with tight seals, relying entirely on waterproof rings to block water. I've been in the repair business for over a decade, and most water intrusion cases I've seen are due to drivers recklessly driving into deep puddles or floodwaters where the water level rises above the door sills. The high water pressure damages the seals, allowing water to enter. The symptoms of water intrusion are very obvious—the oil mixes with water and deteriorates, gear shifts sound like metal grinding against metal, and in severe cases, you can't even shift gears, leading to a completely rusted and scrapped transmission. I recommend avoiding waterlogged roads when driving, not taking risks by driving through water during rain, and checking the condition of the seals during regular maintenance. Older cars especially need new seals replaced to avoid headaches. If water does get in, never force the car to drive—it must be towed to a professional shop for water drainage and oil replacement. Not only is it time-consuming and costly, but inexperienced handling can also damage more components. Prevention is always the best approach—take good care of your car when driving.
My car's transmission got flooded before. That time during heavy rain, I tried to plow through a puddle for convenience, and ended up with jerky gear shifting that was unbearable. The repair cost me several thousand. Transmissions are tightly sealed and not prone to water ingress unless submerged above the door sill or with damaged seals. Older cars have higher risks due to aging gaskets. I've learned my lesson now - I stay more vigilant while driving, detouring or slowing down when encountering deep water, never forcing through. During regular maintenance, I remind mechanics to check transmission seals and fluid condition. Flooded fluid turns milky white - early detection saves money. Repairing water-damaged transmissions is labor-intensive and expensive, requiring fluid flushing and possibly part replacements - more trouble than it's worth. From daily usage perspective, protecting your transmission means avoiding major expenses.
