Although the lubricating oil strainers perform satisfactorily under normal operating conditions, they cannot trap particles of metal and dirt which are fine enough to pass through the mesh. These fine particles can become embedded in the bearing metal and cause wear on the bearings and journals. These fine abrasive particles passing through the gear teeth act like a lapping com-pound and remove metal from the teeth. Water in the oil is extremely harmful. Even small amounts soon cause pitting and corrosion of the teeth.
Acid can cause even more serious problems.
The oil must be tested frequently for water, and periodic tests should be made for acid content. Immediate corrective measures must be taken when saltwater is found in the reduction gear lubricating oil system. Occasionally gross contamination of the oil by saltwater occurs when a cooler leaks or when leaks develop in a sump. The immediate location and sealing of the leak is not enough. Additional steps must be taken to remove the contaminated oil from all steel parts.