Water can corrode metallic parts of the transmission, fry the electrical parts, contaminate the fluid, and damage the seals. In fact, water can easily lead to catastrophic transmission failure. Therefore, keeping water out of the transmission system is vital to its health, and you can only keep the water out if you know how it gets there in the first place. Here are three possible ways in which water may get into the transmission:
One of the functions of the transmission fluid is to cool the transmission system. However, this heat has to go somewhere too, so the fluid also has to be cooled. For this reason, a fluid line runs from the transmission through the radiator to exchange its heat with the coolant.
The coolant is a mixture of glycol and water. Therefore, damage to this part of the radiator may lead to fluid mix-up. Common causes of radiator damage include collisions, corrosion, and overheating. Therefore, check your radiator for punctures, especially after a collision or overheating episode. Fix the damage before it contaminates the transmission with water.
Water can also get into the transmission fluid via the dipstick. This may be rainwater, water for washing the car or condensed moisture on humid days. Of course, this only happens if the dipstick seal is either missing or damaged. The usual cause of damage to the dipstick is normal wear and tear. Therefore, check regularly to see if this seal is in place, and get a replacement if it is missing or damaged. It will only cost you around $50 and save you more costly repairs.
The transmission vent is meant for regulating atmospheric pressure inside the transmission pressure. Unequal pressure interferes with the smooth flow of transmission fluid. The vent also allows heat to escape the transmission and cool air to enter the system. Unfortunately, driving through water—for example, if the road is flooded—may cause water to flow through the vent into the transmission. This is one reason it isn't advisable to drive through deep floods.
The amount of water in the transmission, and how long it has been there, determines the extent of the damage. Therefore, you may have to replace the transmission if it is flooded with water and you did not have it fixed in time. Consult your mechanic to see if this is what you need or if the transmission can be fixed by flushing and rebuilding it. Contact a company like H & S Tire & Auto Center for more info.