VEHICLE IS ALL WHEEL DRIVE FULL TIME. HAS LOW MILEAGE AND BEEN REGULARLY MAINTAINED BY AUTHORIZED DEALERS. AT 65,000 MILES THE CAR BEGAN EMITTING HIGH PITCHED SOUNDS ORIGINALLY THOUGHT TO BE FROM NEW TIRES(4 PUT ON CAR). IT WAS LATER DETERMINED AFTER SEVERAL THOUSANDS MILES THAT AT A MINIMUM THE BEARINGS IN THE FRONT DIFFERENTIAL WERE BAD AND AT LEAST ONE AUTHORIZED DEALER HAS CLAIMED THAT THEY THE REAR ARE BAD AS WELL. BOTH DIFFERENTIALS SIMULTANEOUSLY. OBVIOUS CONCERN FOR SEVERAL REASONS: 1)THE CAR IS ALL WHEEL DRIVE FULL TIME. EXTENSIVE DAMAGE TO THE DIFFERENTIALS AT HIGH SPEED OR WHILE TOWING AS A RESULT OF BEARINGS AND GEARS BEING DAMAGED. 2) ALL DEALERS CLAIM THIS IS A REGULARLY OCCURING PROBLEM IN THE JEEP CHEROKEE OF THAT YEAR AS WELL AS OTHERS 3)IT HAS BEEN SUGGESTED THAT THE PROBLEMS WILL OCCUR IN THE SAME TIMEFRAMES THROUGHOUT THE LIFE OF THE CAR IN SPITE OF "REGULAR AUTHORIZED AND SCHEDULED MAINTENANCE" AS HAS OCCURED ON THIS VEHICLE SINCE IT WAS PURCHASED. IN LIEU OF SAFETY CONCERNS IS ALSO THE SUGGESTION THAT IT WILL COST 5-10% OF THE CAR'S PURCHASE PRICE EVERY 65,000 MILES TO REPAIR THIS SAME PROBLEM. *AK