Peter.
You wrote:
3. gear juping when under load (down hill)....
A thought . . . before you start in on dismantling things, with internal gearbox problems on your mind, I suggest you take a few moments to lift the carpet and unscrew the access plate so as you can look at the gear changing links and the anti-torque/rocking stay which (hopefully) is mounted between the power unit (at the bell housing) and the "body". Without this stay doing it's job properly the torque racking the engine can "take over" the gear change links by effectively changing their lengths and so putting the box into neutral. If your car doesn't have such a stay, I suggest you get hold of one and fit it whenever the opportunity arises. Check the setup of the adjustments of the links too. Soggy rubber engine mounts and/or the conical buffers at the front don't help either. This may not be the cause of the problem of course and the problem very well may be internal, but it's worth a moment's time . . . and anyway, that plate has to come off if you are taking the gearbox out!
This suggestion is prompted by my experience of acquiring our second Javelin, which had the engine/gearbox out at the time of purchase. The poor guy I got it from had had the unit out a couple of times and had a go at the gearbox because it was jumping out of gear. It still jumped out when he put it all back together. In desperation he removed it once again and sent it away to be overhauled by an expert (expert in Jowett gearboxes). He had it all ready to go back into the car once more, when that evening, he fell in the shower and broke his back! . . . Anyway, when I put the power unit back into the car and went to take it for a test run . . . guess what? Yes . . it jumped out of gear! And guess what fixed that ???
Best of luck, Peter.
Leo.
R. Leo Bolter,
Palmerston North,
New Zealand.
JCC of NZ - Member No 0741.
JOAC - Member No 0161
Car: Jupiter (E1-SA-513-R)
Skype name = jupiter1951
Messenger name = r.l.bolter"at"massey.ac.nz