Symptoms must be analyzed together
Pump noise alone does not prove internal mechanical destruction. Suction line restrictions, oil level, aeration, and control settings cause identical noise.
Flow & pressure loss
Sluggish machine speed, pressure collapse under load, or inability to reach displacement setpoints stem from wear, pilot control faults, high case drain, or system bypass.
Temperature & case drain
Excessive heat at the pump housing and elevated case drain flow indicate internal slip. Measurements must be evaluated against manufacturer thresholds.
Pre-overhaul system check
Before installing a new or rebuilt pump, verify suction piping, filtration, oil cleanliness, cooling, and relief settings to avoid immediate re-damage.