Gearbox seal leaks are the bane of industrial operations. Because proper lubrication is the lifeblood of enclosed drives, maintaining oil levels is critical to achieving a long service life. When oil starts leaking, immediate corrective action is necessary—but finding the root cause isn't always straightforward. The causes of a leaking seal can vary widely based on the gear type, mounting orientation, operating speed, and surrounding environment. Below is a real-world troubleshooting case study and a breakdown of the primary factors to investigate.