What indication shows the hydraulic fluid needs servicing?

The indication that suggests the hydraulic fluid needs servicing is a red band on the filler plug. The presence of a red band serves as a visual alert that the hydraulic fluid level is below the acceptable threshold, which may require immediate attention. This designation is critical in systems where maintaining proper hydraulic fluid levels is essential for safe and effective operation.

In contrast, a green band typically indicates that the fluid level is adequate, an amber warning light often signifies a caution rather than an urgent need for servicing, and a pressure gauge reading may provide insights into the operating conditions but does not specifically address the fluid level. Thus, the red band effectively communicates the need to check or replenish the hydraulic fluid without ambiguity.