TRANSMISSION WAS REPLACED 3 TIMES DUE TO FAILURE OR LEAKAGE AND THIS TRANSMISSION WAS SHOWING SIGNS OF SLIPPAGE AFTER DRIVING 40 MILES ON HIGHWAY. TROOPER WAS BEING OPERATED ON I-895 IN BALTIMORE AT 50 MPH WHEN SMOKE WAS SEEN IN REAR VIEW MIRROR. TROOPER WAS PULLED TO SIDE AND SON EXITED VEHICLE TO CHECK ENGINE. TROOPER IMMEDIATELY BURST INTO FLAMES RESULTING IN A TOTAL LOSS OF VEHICLE AND CONTENTS.*AK