Only 5th gear is usable

[Falco]

I was driving nice and easy in 3th gear when suddently it went out of gear. The only gear that I could catch was 5th. The gear stick are able to move more than usually. "Well the gear cable is broke, I thought", but no, noting is wrong with the gear cabel. The problem is inside the gear box.
Is it possible that one ore more of the bolts inside the side cover of the gearbox is loose - like mentioned in some of the other topics ?
Is it posible to take out this cover without having to remove the driveshaft etc. ??
Is it just: remove the cover, tighten the bolts, replace the cover and then drive with a big smile ??

[Enright]

I think that this is a problem with the selector box, which bolts onto the top of the gearbox.
G UK had this problem with his old Elan but I can't remember how he fixed it (apart from by driving it into a tree, but that was a different sort of 'fix' and I wouldn't recommend it!).
In the short term you can simply unbolt the selector box, move the selector forks with a screwdriver to shift the gearbox into neutral and put it back together. The car is then driveable but you mustn't use 5th or it will instantly jam again.

[saska]

I was driving nice and easy in 3th gear when suddently it went out of gear. The only gear that I could catch was 5th. The gear stick are able to move more than usually. "Well the gear cable is broke, I thought", but no, noting is wrong with the gear cabel. The problem is inside the gear box.

First determine where, exactly, is the problem as Enright suggests:
1. Disconnect both gear cables from the selector box. Can you then get in/out of all gears just using the selector levers -- if you can then the cables are suspect. You may not be able to readily see the cable failure. If you can't get all gears using the selector box levers:
2. Remove the selector box. Use a screwdriver to try to get in/out of all gears via the hole where the selector tongue goes. If you can get all gears then the selector box has a fault. There is a fifth to reverse lockout mechanism screwed into the top/front of the selector box that has been known to cause problems. If you can't get gears by manipulating the gearbox selectors directly then the problem is in the gearbox.
3. If this is the case then initially remove the gearbox endplate and check the peening marks on both large nuts to see if they've moved. You can remove the endplate without having to remove anything else but you'll have to do something about a gasket upon re-assembly.
4. Report back with what you've found.

Photos:
Fifth/reverse lockout:


Gearbox endplate:


Shaft nuts with peen points:

[Falco]

Dear Saska and Enrigth,
Thank you for the replies and the pictures, I will test the surgestions in the weekend and let you know the outcome.

[rip]

If the large nuts have come loose, it is unlikely that you can just tighten them up & go: if the gears slide down the shaft, shims will have dropped out of place. If you then tighten the bolts, you will simply be jamming the shims in their incorrect location. There is a way of spinning the gears to make these re-locate but my mechanic lost me by this point when he explained it

Fingers crossed that it is something more simple.

[G UK]

G UK had this problem with his old Elan but I can't remember how he fixed it (apart from by driving it into a tree, but that was a different sort of 'fix' and I wouldn't recommend it!).

I managed to fix this before doing my lumberjack impression thank you.

Falco,
Your problem sounds slightly different than the one I had but it is worth checking that the selector box bolted to the top of the gearbox isn't sticking in 5th. To do this remove the selector box and position the selector in 5th, now try and move the selector back to the reverse position whilst keeping it hard over on the lateral 5th-Reverse side of the selector. It should move back to the neutral position before locking but if it locks whilst still in 5th the locking cam has moved and needs resetting or removing.

[Specky]

Your gearbox issue sounds slighty different to the normal 5th gear problem, in what ever guise they normally appear. I'd go back and double check the cables. Look carefully at the front attaching mount ( where they mount to the gearbox, adjustment point). You should have two retaining clips ( either a flat E- clip or a round spring clip). It cracks under them on the plastic housing. The two tell tale signs are, the clips missing and the crack opens up on gear selection. ( a two man job to see, one to operate, one to view).

You can take the cover plate off quite easy, you'll lose about 1/2 a cup of oil max.

Let us know how you get on.

TTFN