Can Water Enter the Transmission Vent Plug?

[LaMatthew]

Transmission vent plugs can allow water ingress. Below are three levels of water intrusion in transmissions: Severe Water Intrusion: This can be identified by observing the oil-water mixture. If the transmission has significant water ingress, it can be directly observed during oil drainage. Specifically, drain the transmission fluid—if there is substantial water ingress, the color and viscosity of the oil-water mixture will indicate the severity. Moderate Water Intrusion: White deposits in the oil pan suggest moderate water intrusion. If oil drainage alone doesn't confirm water ingress, further inspection is needed. This involves removing the oil pan for observation. When water mixes with transmission fluid, it forms a white emulsion that adheres to the oil pan. The presence of such deposits confirms moderate water intrusion. Mild Water Intrusion: Partial rusting of internal screws indicates mild water intrusion. If the above methods don't yield conclusive results, disassemble the transmission to inspect the screws. Water-oil mixture corrodes steel screws, so rusted screws confirm mild water intrusion with relatively low water content.