Does your Austin jump out of Gear?
Overhauling the gear selectors of a 4 speed box.

Gill gearbox 1

If the gearbox jumps out of gear it is time to change the balls and springs in the selector forks. Having removed the box from the car, it should be secured in a frame to hold it upright and be accessible from both ends and top. The first step is to remove the cover and gear change gate assembly.

With your fingers try moving each fork. If the spring is worn the ball will not lock the fork in the neutral or meshed position .

Gill gearbox 2

The first step to removing the selector bars is to remove the nuts and locking plate at the back of the box.

Gill gearbox 3

Next step is to drive out the selector bar with a drift.

Gill gearbox 4

Care must taken not to lose the shims on the back of this shaft.

When removing the bar from the fork, catch the ball with a small magnet. This can be passed through from the back of the box as the bar is removed.

Gill gearbox 5

Here you can see the hole in the fork for the ball and spring. Make certain you remove all of the spring if it has broken.

Gill gearbox 6

The picture shows old and new springs and balls.

Gill gearbox 7 Clean all parts prior to re-assembly with new balls and springs. Start re-assembly with the reverse fork. Make sure that the fork slots into the grove on the gear. As you slide the selector bar into the fork replace the new spring and ball into the hole in the fork.

Hold the ball in position with the magnet until the threaded part off the bar is past the ball then compress the ball and spring as the bar is driven through. As this is very fiddly a spare of hands will help!

Screw the bar home but do not tighten as it will need adjusting later. Follow this with the 3rd -4th fork and bar then the 1st -2nd fork and bar. Make sure that the flat on the bar lines up with the locking plate.

Then replace the locknuts. Tighten the nut on the 1st-2nd bar. Then replace the gear change assembly. The other two bars may need some adjustment to get all three gates inline so the horseshoe shaped plate moves freely side to side .

Gill gearbox 8

When this is done tighten the other two locknuts. You can now refit the top cover. The box is now ready to be refitted.

This article, written by Chris Gill, originally appeared in CA7C Seven Focus in May 2013 pp26-28.

Does your Austin jump out of Gear? Overhauling the gear selectors of a 4 speed box.

Does your Austin jump out of Gear?
Overhauling the gear selectors of a 4 speed box.