Contaminants change the viscosity of the oil and can cause corrosion of engine parts if left in the engine too long. Farm tractors are designed to be operated with additional weight or ballast when pulling heavy loads to prevent wheel slip. Insufficient ballast can cause excessive wheel slip and increased fuel consumption. Some slip is desirable to reduce the wear and tear on the drive train of the tractor. Check drive tires for excessive wear.
Worn tires can cause wheel slip from poor traction and increased fuel consumption.
Radial ply drive tires have more flex in the side wall of the tire which results in more traction when compared to same size bias-ply tires. Tractors that pull heavy loads are good candidates for radial ply tires. The increased costs of radial tires is usually more than offset by the increased traction, fuel savings and extended tire life. Inspect the inflation pressure in drive tires and inflate according to manufacturers recommendations based on your loads and traction needs. Increasing inflation pressure by one or two pounds can improve fuel efficiency significantly from reduced rolling resistance.