HAD BEEN INTERMITTENTLY SEEING WHITE SMOKE COME FROM UNDER THE HOOD OR FRONT UNDERCARRIAGE OF VEHICLE. NO CAUSE VISIBLE TO THE EYE WAS FOUND. ON DATE IN QUESTION, ENGINE AREA CAUGHT FIRE WHILE DRIVING AT A LOW RATE OF SPEED. VEHICLE TOWED TO COLLISION SHOP WHERE IT WAS DETERMINED THAT TRANSFER CASE/ PUA UNIT WAS "BAD" AND CRACKED. NO COLLISION OR EXTERNAL DAMAGE CAUSED IT. PART SIMPLY CRACKED FOR AN UNKNOWN REASON ACCORDING TO CHRYSLER COLLISION/BODY SHOP. DAMAGE NOT COVERED BY AUTO INSURANCE BECAUSE IT WAS SPONTANEOUS. FRONT END OF VEHICLE PULLS, IGNITION STALLS, ELECTRICAL PROBLEMS, BRAKES (PADS, ROTORS & OFTEN CALIPERS) & TIRES MUST BE REPLACED EVERY 4-6 MONTHS. UPON REGULAR MAINTENANCE INSPECTION THERE IS NO SIGN OF PROBLEMS WITH BRAKES & TIRES BUT FULL REPLACEMENT IS USUALLY REQUIRED WITHIN SEVERAL WEEKS OF INSPECTION. *TR