UPON ENTERING THE HIGHWAY, THE TRUCK SUDDENLY STARTED HAVING PROBLEMS, THE R.P.M. GAUGE STARTED FLUCTUATING FROM 1000 TO 3000 R.P.M., IT SQUEALED AND JERKED INTO GEAR AND A POPPING NOISE WAS COMING FROM THE RIGHT SIDE OF THE FRONT END. THE DEALER COULD NOT FIND ANY PROBLEM, BUT HE SUGGESTED THAT IT COULD HAVE BEEN THE CLUTCH FAN SLIPPING. CONSUMER EXPERIENCED AGAIN WHAT HE FELT WAS TRANSMISSION PROBLEMS BUT THE LIGHT NEVER FLASHED ON THE OVERDRIVE COLUMN SO TAKING NOTE OF WHAT WAS HAPPENING AND CONTINUED DRIVING. THEN THE LIGHT STARTED FLASHING ON THE OVERDRIVE COLUMN, WITHIN SECONDS, CONSUMER NOTICED A LARGE PUFF OF BLACK SMOKE COMING FROM UNDER THE TRUCK, THE R.P.M. GAUGE WENT TO BELOW 1000, THE TRUCK LOST ALL POWER, AND THE CAB STARTED FILLING WITH SMOKE AND FIRE WAS ESCALATING UNDER THE TRUCK AND HOOD. POSSIBLE ENGINE FAILURE. *YD