N ORDER TO ELIMINATE CONTAMINANTS, gearboxes are typically drained quarterly, semi- annually or annually. Following drainage, at aleast five percent of the old oil usually remains in the gearbox. For this reason, it is good practice to drain oil shortly after shutdown to prevent the accumulation of sludge and contaminants in the bottom of the sump. Otherwise, when the gearbox is refilled with fresh lubricant and restarted, the contaminants become resuspended, defeating the purpose of the oil change.

Drew Troyer of the Noria Corporation offers the following tips:

1. Drain the old lubricant within 15 minutes of shutdown and prefilter the fresh oil.
2. Rather than draining the oil to eliminate contaminants, periodically filter the oil with a portable filtration cart while the machine is in operation. Make use of oil analysis to determine when the oil requires changing. Employing this strategy reduces overall maintntance expenses and extends equipment life, and requires little investment.
3. Install full time filtration on the gearbox and use oil analysis to determine when to change the oil. This strategy also reduces maintenance expenses and extends equipment life, but requires more upfront investment.

"Alternative No 1 helps, but alternatives No 2 and 3 are the best," says Troyer. "Most scheduled oil changes can be eliminated with the one-two punch of filtration and oil analysis. This strategy reduces lubricant and labor costs - and the fact that your gearboxes will last longer is a major bonus. Plus, the maintenance of the fluid can typically be performed during run-time, shrinking the task list during scheduled outages."

AMSOIL offers state-of-the-art oil analysis at Oil Analyzers, Inc.