MGB Gearbox Selector Shaft Tensioning

[Simmo]

There are three screws just behind the bell housing which bear on a spring and ball to put tension on the operating Rods.
Does anyone know how to manover the gearbox into a position in order to remove these bolts so that I can increase the tension on these springs with the introduction of a spacer.
At least one anyway, so as to hopefully stop the jumping out of top gear.
Any suggestions gratefully accepted

 

[Joe Schlosser]

I am guessing that increasing the tension on the detent springs will not correct the problem. Your issue is most likely a worn 4th gear syncro.

 

[dklawson]

I am guessing that increasing the tension on the detent springs will not correct the problem. Your issue is most likely a worn 4th gear syncro.

Agreed. If not wear in the synchro it could be wear in the selector fork or the syncro hub.