Hi all.

Unfortunately for me I have to take off the top of my gearbox and stretch out the detent spring by 5mm. Rick Pembro has suggested this to me, its a lovely smooth gearbox rebuilt my him years ago. It sometimes glides gently out of 3rd gear recently but its otherwise faultless.

Does the top of the gearbox just detach and reattach easily? A see the fixings, I just worry about how the actual selector shaft part works.

Thanks!

The gearbox lid will be under a little tension from the detent spring.

It's not unknown for these springs to ping, and disappear, never to be seen again.

The selector shafts are all contained within the main body of the box.

I don't think there is a gasket, just sealant. Old sealant should be cleaned up and new applied.

Take a photo of where any brake pipes attach, to help determine nuts and bolts for reassembley.

Straight forward enough, but watch out for your back as it's at an annoying angle when bending over to the middle of car.

And put the gearbox in neutral before taking off the lid. This later easier in reassembly.

And when put the lid back, keep focused the gear lever goes to right place on "grooves" at selector rods. If not, it is very easy to bend the rod/rods when tighten the lid screws...

Don't ask how I know...

When refitting the lid, (assuming it's a disc-brake box), the bolts and studs alternate, so going clockwise, starting at the one at the back corner near the speedo cable drive, it goes:
stud for earth cable,
bolt,
stud for air filter support,
bolt,
stud for brake pipe bracket,
bolt,
stud for brake pipe bracket,
bolt.

Thanks all, amazing help as always.

I changed the linkage rubbers today so I'll see if that makes a difference. Somehow I had 3 washers on what I had on there. Refitted with a washer top and bottom of the end that attaches to the end of the dash lever.

One is wavy, but I lost the other wavy one recently so is it OK having a flat washer on one end of that?

To be honest, I've never had this effect from bad rubber bushings even when they've been completely ruined, so I expect I'll be popping the top off the box soon.

It's only done it once since new bushes. And not really popping out of gear, just I was on overrun in 3rd and went to accelerate and it had ever so gently glided into neutral.

Hmm, maybe I should still do this spring. But it definitely seems less urgent now.