WHILE DRIVING AT APPROXIMATELY 65MPH, I ATTEMPTED TO PASS ANOTHER VEHICLE TO MY RIGHT TRANSMISSION FIRST APPEARED TO DOWNSHIFT FROM 5TH TO 4TH AND THE CAR ACCELLERATED NORMALLY, BUT SUDDENLY THE ENGINE RPM INCREASED DRAMTICALLY, THE CAR SUDDENLY STARTED DEACCELERATING AND FISHTAILED WIDELY. IT SIDE SWIPED THE CENTER DIVIER OF THE FREEWAY, DAMAGING THE LEFT SIDE. IT APPEARS THAT THE TRANSMISSION SUDDENLY DOWNSHIFTED TO A MUCH LOWER THAN NORMAL GEAR (LIKELY 2ND) AND THE ENGINE RPM THAT WENT OVER REDLINE, CAUSING THE ENGINE GOVENOR TO SHUT DOWN THE ENGINE AND THE LOWER GEAR TO PROVIDE EXCESSIVE ENGINE BREAKING, CAUSING THE LOSS OF CONTROL.*AK