ENGINE MAINTENANCE - Engine Lubrication and Filter Intervals Determining Type of Vehicle Application for Engine Oil Drain Intervals 2 Y53-1181-1K1 (08/2018) 41 Severe Duty - Vocational * Normal Duty - Line Haul Fuel Consumption Less than 6 MPG (2.6 km/L) 6 MPG (2.6 km/L) or greater Gross Vehicle Weight Greater than 80,000 lb. (36,300 kg) 80,000 lb. (36,300 kg) or less * Vocational vehicle applications include: Agriculture, Concrete Mixers, Construction, Crane, Dumps, Emergency/Fire, Heavy Equipment, Loggers, Mining, Oil Field, Refuse, Pick-up & Delivery, Snowplows, and Wrecker.