What type of fluid is typically checked using a dipstick?

Transmission fluid is typically checked using a dipstick because it allows for accurate measurement of the fluid level within the transmission system. The dipstick provides a clear indication of whether the fluid is at the appropriate level, which is essential for the proper functioning of the transmission. Proper fluid levels help ensure that the transmission components are adequately lubricated, which can prevent overheating and excessive wear.

In contrast, other fluids mentioned in the options have different methods of checking. For example, brake fluid and coolant are usually checked by inspecting their reservoirs, while power steering fluid might also have a reservoir but does not typically use a dipstick for level measurement. Therefore, the use of a dipstick specifically for transmission fluid makes it the correct choice in this context.