TM 10-3930-671-24 Recommended PM and Lubrication Schedule PM Interval: Note * Oil change interval may A = 8-10 hours, or daily be determined by commercial B = 50-250 hours, or every month (Typical PM interval) laboratory analysis of oil. C = 450-500 hours, or every 3 months **   Air filter change interval may be D = 900-1000 hours, or every 6 months determined by installing air cleaner E = 2000 hours, or every year restriction indicator. † = 800 hours after initial readjustment (See Section 4.9, Air Filter) F-40