hello,
my jumping problem was down to er... careless gearbox building! I had one of the selector rods the wrong way round, so unless you've been dismantling boxes in your sleep (there was a time I could have done that!) it won't be your problem.
Does it jump out when you lift off? I think a worn syncromesh can do that (it would be a gearbox in bits job I'm afraid)
In my (humble) opinion, it sounds like a new clutch is on the cards so go and get that done, If you have a spare gearbox knocking about get it swapped over, if not don't worry and just have fun with the van with the new clutch and see what happens (keep an eye on it).
You could change the gearbox oil and have a look at the stuff that comes out, if its all manky with shiny gold bits in, then you may have a syncromesh problem.
Out of interest do you have an overdrive?
hope some of this helps
cheers
Rupert
"With great cars comes great responsibility"
www.littleyellowcar.co.uk
