the speedo in my new wagon is jumping around all over the place and sometimes not at all.... anyone had trouble with this before , and whats the most likely cause. could it be the sensor on the gearbox and more likely the actua gauge in the cluster??????? ?????

sounds more like the wiring or connection before anything, check the thing is connected properly at the gearbox end.

Similar problem ..... unsolved.

check that everything is earthed that needs to be.

I assume you are using the electronic speedo from the S13?

yeah i'm using the s13 cluster. my old ca18det ute did the same thing but not as bad. sometimes it will sit on 20 or 40 when accelerating or decelerating. just sits there and won't go up or down so thats why i was thinking not an earth... it doesn't always jump around sometimes it just won't move . if i was to use another mechanical speedo what sender or sensor thingy should i use, or cable etc. ????????