Overhead Crane Gearbox, Drum & Sheave Faults: Causes, Symptoms & Repair Guide
The gearbox, drum, and sheave form the mechanical core of any overhead crane hoist mechanism — and when any one of them fails, the entire lift stops. These three components are also where most unplanned maintenance calls originate, because their failure symptoms overlap and early warning signs are easy to misread. A grinding noise, for instance, could point to a gearbox with insufficient backlash, a drum with a worn groove, or a seized sheave starved of lubrication — three very different corrective actions. This guide helps maintenance engineers and plant managers do two things quickly: identify which component is failing based on what they are seeing or hearing, and know the exact wear threshold at which replacement is no longer optional. For teams evaluating suppliers or spare-part sourcing, the compliance section at the end covers the certification documents worth requesting before a part ships. Diagnose the Fault First: Symptom Quick-Reference Before pulling tools, match the symptom to the component. The table below maps observable signs to the most likely source and the urgency level. What you are seeing or hearing…