What was found
AFTER TAKEOFF, A PUNGENT, STAGNANT, DIRTY, MUSKY ODOR UNLIKE BURNING OR SMOKE, FILLED THE ACFT COCKPIT AND CABIN. WENT AWAY WITHIN 10 MINUTES. NO EICAS OR OTHER DEFECTS NOTED. ACCOMPLISHED TC 21-20-00-810-803A. REPLACED BOTH RECIRCULATING FILTERS IAW 21-24-02. RAN ENG AND PACKS NO ODOR NOTICED.