A loader operator reports that the machine's primary hydraulic pump is producing an unusual whining noise and the boom and bucket functions are noticeably slower than usual, even without heavy loads. The hydraulic oil level appears to be correct. What initial troubleshooting step should a technician perform?

Question: A loader operator reports that the machine's primary hydraulic pump is producing an unusual whining noise and the boom and bucket functions are noticeably slower than usual, even without heavy loads. The hydraulic oil level appears to be correct. What initial troubleshooting step should a technician perform?

Answer options: ✅ Check for air ingress into the hydraulic suction line.

• Replace the main hydraulic relief valve.
• Adjust the engine governor to increase RPM.
• Completely drain and refill the hydraulic fluid reservoir.

Correct answer: Check for air ingress into the hydraulic suction line.

Explanation: A whining noise in a hydraulic pump, especially accompanied by sluggish operation, is a common indicator of cavitation caused by air in the suction line or a restricted suction filter. Air ingress causes the pump to work harder and less efficiently. Replacing the relief valve or adjusting engine RPM would not address this root cause. Draining and refilling the fluid might help if the fluid is contaminated, but air ingress is more likely with these specific symptoms.