HOT and COLD markings on a transmission dipstick are used to indicate changes in what?

• A. To indicate oil color
• B. To indicate engine oil brand
• C. To indicate oil type
• D. To indicate changes in oil viscosity with temperature

Answer: (D)

Temperature affects how thick or thin transmission fluid is, and it also causes the fluid to expand a bit when it’s hot. The HOT and COLD marks on the dipstick are there to show the proper level for those two temperature states. When the fluid is cold it’s thicker and sits lower on the stick; when it’s hot it’s thinner and expands, so the level sits higher. Using the two marks ensures the fluid level is within a safe, lubricating range whether the system is cold or at operating temperature. These marks aren’t about color, brand, or type of fluid.