How Deep Does Water Need to Be for the Transmission to Take in Water?
2 Answers
After a vehicle wades through water, the transmission may take in water under the following circumstances: Water level exceeds two-thirds of the wheel height: The probability of the transmission taking in water is around 80% to 90%. Water level reaches the dashboard position: The transmission has 100% taken in water. Generally, there are two scenarios when a vehicle wades through water: Vehicle in motion: As long as the vehicle is still moving and the engine has not stalled, even if the transmission is submerged, it usually won't take in water. Although the transmission has a vent hole, the pressure inside the working transmission prevents water from entering. Vehicle stationary: In this case, the transmission is not operating. If the transmission is submerged in water, water can enter through the vent hole. The transmission must be inspected, and the transmission fluid must be replaced. If not addressed within four hours and the vehicle is brought to the shop after three to five days, even after repairs, transmission issues may still arise within five months.
I've driven many cars, and once when the water depth reached the center height of the tires, about 25 to 30 cm deep, the transmission got flooded, costing me several thousand in repairs. The reason was that the transmission has vent holes, and when the water pressure is high, water seeps in, mixing with the oil and causing gear wear. Different car models have different risk points: sedans are usually in danger below 25 cm, while SUVs might be okay up to 40 cm. When wading through water, use a low gear and maintain a steady speed—avoid accelerating or braking suddenly to reduce risks. But never attempt it if the depth exceeds half the wheel height; if water does get in, you'll hear unusual noises or experience jerking—stop immediately and check the fluids. I always keep a wooden stick in my car to measure water depth, avoiding wading at night when visibility is poor. Regular maintenance of the vent holes is also crucial to prevent more severe flooding due to blockages.
