VEHICLE FIRE ORIGINATING FROM PLASTIC GAS TANK.*MR THE CONSUMER NOTICED A SMALL LEAK ON THE RIGHT REAR TIRE. THE TIRE WAS CHANGED WITH THE COMPACT SPARE AND THE CONSUMER PROCEEDED ABOUT 35 MILES TO HAVE THE TIRE REPAIRED. THE CONSUMER WAS MAKING A TURN WHEN HE NOTICED A CLOUD OF SMOKE COMING FROM THE VEHICLE. WHEN HE PULLED OVER HE SAW THAT THE VEHICLE WAS ON FIRE AT THE REAR AXLE. AXLE OIL WAS POURING OUT AND COVERED THE PLASTIC FUEL TANK WHICH WAS ALSO IN FLAMES. THE FIRE WAS EXTINGUISHED AND THE VEHICLE WAS TOWED TO A DEALER FOR TEMPORARY REPAIR. THE CONSUMER WAS TOLD THAT THE PROBLEM WAS CAUSED BY USING THE COMPACT SPARE WITH A SMALLER DIAMETER ON A ALL TIME FOUR WHEEL DRIVE VEHICLE. BOTH THE FRONT A REAR AXLES WERE SO HOT THAT THE COVER GASKETS MELTED. THE MANUFACTURER DENIED ANY RESPONSIBILITY. THE 1996 JEEP GRAND CHEROKEE WAS RECALLED (RECALL # 757) FOR A SIMILAR PROBLEM AND THE CONSUMER BELIEVES THE SCOPE OF THE RECALL NEEDS TO BE EXTENDED TO INCLUDE OTHER YEARS. THE SPARE TIRE USED CAUSED FRICTION BETWEEN THE BOTH FRONT AND REAR DIFFERENTIALS, RESULTING IN FLUID LOSS AND A SPARK WHICH STARTED THE FIRE. *PH *NLM