Gearbox experts - help needed!

While doing a complete rebuild of my gearbox I have encountered a problem where I need help.
Everything works OK and the gearbox is assembled according to Workshop Manual, Old Britts article and watching the Mick Hemmings DVD frame-by-frame... but:

When tightening up the mainshaft nut the sleeve gear locks to the mainshaft!

Inner cover in place and everything shifts ok, mainshaft threads are well through the inner race of the bearing, shifting to neutral the sleeve gear just has a slight drag when turning the mainshaft but as soon as I tighten the mainshaft nut up the sleeve gear turns (and locks) with the mainshaft.

Have studied the diagrams over and over but can not really understand why this is happening.

Thanks in advance,
Peter

I dont see how that could happen either! Is the mainshaft free to move in and out of the sleeve gear? There would have to be a burr or damage of some kind inside the sleeve gear or on the mainshaft so that it has something to pull against and lock up. Alternatively, is the clutch circlip in place and is the sleeve gear fully into the bearing and bearing fully into housing? It might be possible for the circlip to act as a stop if these parts are not fully seated. It is possible the shaft is bent at the point where it exits the sleeve gear on the clutch side. If you have fitted new bushes in sleeve gear that would make it worse. Just guessing!

Forgot to mention:

Gearbox is on the workbench (or in the vice), sprocket on sleeve gear and an old clutch centre on mainshaft.
I'm also leaning towards that something is bent or misaligned although the mainshaft is brand new.

Tearing it apart again...


Thanks,
Peter

Peter, I had the same problem lately. It appeared the radius of the inner race (sleeve gear bearing) was machined to tight (in fact there was almost no radius at all). When I got the bearing and sleeve gear out of the box there was an 0,03" gap between the bearing and the sleeve gear! Got myself another proper bearing which solved the problem.
Good luck.