ABYC Diesel Practice Exam

What is a common sign of transmission fluid contamination?

1. Strong odor

2. Milky color

3. Excessive viscosity

4. Presence of bubbles

The correct answer is: Milky color

A milky color in transmission fluid is indeed a common sign of contamination and typically indicates the presence of water or coolant mixed with the fluid. The transmission fluid is normally a clear or lightly tinted red or brown, and if it takes on a milky appearance, it suggests that it has been compromised. This could lead to serious operational issues within the transmission, as the fluids are not working in their intended capacity, leading to potential damage over time. The other indicators, while they can signal various issues with transmission fluid, do not specifically denote contamination in the same way. For example, a strong odor may hint at overheating or degradation, excessive viscosity could indicate age or contamination but is less specific to the type of issue, and the presence of bubbles may point to aeration or foaming rather than direct contamination. Therefore, recognizing a milky color is critical for diagnosing the particular problem related to fluid integrity and potential water ingress.