phillips r770 autochanger problem

My Philips 6 disc autochanger that came factory fitted with my Rover
45 isn't performing very well. Cd's playback skip when I drive over
the slightes bump or minimal vibration. It does this instantly, there
is no time delay. I thought there would be some anti shock delay. Is
this something I have to put up with wih in-car audio, or is there
something wrong with it?

If I replace it with a 10 disc Sony autochanger, would I have to
replace the R770 head too? Otherwise how would I access discs 7-10?

Thanks, David