What is the purpose of performing both a cold and hot check on transmission fluid?

The purpose of performing both a cold and hot check on transmission fluid primarily revolves around confirming fluid presence and operational level. When checking transmission fluid, the vehicle's operating temperature significantly affects the fluid's expansion and level. A cold check provides a baseline measurement while the fluid is at its lowest volume, ensuring that there is enough fluid in the system when the vehicle is not running. Conversely, a hot check allows the assessment of the fluid's level when it's warmed up, which is crucial because the transmission fluid expands as it heats up.

This dual approach ensures that the transmission has adequate fluid under both conditions and is essential for maintaining optimal performance and preventing potential damage to the transmission due to low fluid levels. Although assessing viscosity or observing fluid color can offer insights into the condition of the fluid, those factors are secondary to ensuring that there is sufficient fluid volume at both temperature states. Similarly, measuring wear and tear on components or accurately assessing fluid temperature may have their own importance but are not the primary reasons for conducting these specific checks.