Abstract: A device for conveying lubricant oil from a gear housing through an external treatment unit for treatment or reconditioning, and back to the gear housing. The gear housing is adapted for being partially filled with a liquid lubricant or oil. The external treatment unit is fixed to the gear housing unit. A rotatable gear wheel in the gear housing moves the lubricant into an inlet duct leading to the external unit. The inlet to the inlet duct is in the vicinity of the periphery of the gear wheel in the gear housing. The inlet into the inlet duct is located generally in the vicinity of the surface of the pool of lubricant and at least in part beneath the surface. A separate outlet connection from the external unit receives reconditioned lubricant. That connection has an outlet back into the gear housing, above the surface of the pool.