My 2005 prius seems to have developed a unique problem. I have not seen it discussed before on this forum. While traveling at varius speeds, it switches the drive system to neutral. It has happened a couple to times now, switching from drive to neutral and once from reverse to neutral. Has anyone experienced this before? Any clue as to what may be causing it? I feel I'm going to have to take it in to be serviced, but with an intermittent problem, they may not be able to locate the fault. Thanks.