So I removed the gearbox from the chassis and there are these three holes that I don't know what are for? They were just filled with silicone....?

Should I just seal them up again?

They're a bit near the end of the box but could be for the selector shaft detent springs but they're uniformly spaced and on the side where the selector rods are.

Shine a torch up them and see what you can see and report back. No idea why some dingleberry would drill holes anywhere on a gearbox let alone there?

they are for the detent springs which have a ball bearing on the other end
there should be a alloy blanking plug to hold the springs in place

Here is the closeup



What's the purpose of detent springs? Anyone sell them and the blanking plugs?

The selector shafts have notches in them so that once the gear is selected the shaft stays in this position by the ball bearing being forced against the selector by a spring.

I would suggest the best option is to remove the end of the box so that the holes can be tapped for large allen head grub screws. I say this cos if they've been drilled out then replacement plugs may be a loose fit.

As for the ball bearings they just need to be marginally smaller than the hole and the spring, well send Dangerous on here a PM as he may be able to help you out with them or tell you size n length to buy.

The detent ball and spring are actually on the other side of the selector shafts,the spring and ball are fitted through these holes and the selector rods slide in and keep them in place the holes are then fitted with blanking plugs to keep the dirt out.

Cool. Just need the blanking grub screws then

Give the holes a spray with some solvent to remove all traces of oil and put some silicone in them- not enough though to fill the whole cavity,just enough to keep any shit from getting in.

Cool, thanks for that guys Will clean it out and probably just seal it with some knead it epoxy