WAS DRIVING & WAS MAKING A LEFT HAND TURN WHEN ANOTHER VEHICLE HIT REAR PASSENGER'S SIDE BEHIND WHEEL WELL. UPON IMPACT, REAR BACK BUCKET SEAT BECAME DISLODGED FROM SEAT TRACT. CHILD SEAT WITH CHILD IN IT WAS RECLING BACKWARDS. MANUFACTURER INDICATED PROBLEM WAS RIVER'S FAULT. *AK