Excavator Hitachi EX750-5 EX800-5 ZX800 ZX850 EX1100-3 EX1200-5 Swing Motor Assembly 4237779 4334727 4388207 Common Faults 1. Weak swing with slipping during startup. 2. Abnormal swing noise, including gear howling or knocking sounds. 3. Oil leakage at the housing and flange seal. 4. Swing assembly overheating with elevated oil temperature. 5. Swing jerking and slow rotation. 6. Brake failure resulting in free slewing. Purchasing Recommendations 1. Verify the machine model