So it was the third ribcase gearbox in almost as many years. Always first
and reverse, followed by 4th. This time the seemingly perfect 'low mileage
since rebuild' box was grinding whenever it was in reverse and would jump
out as soon as any load went on it. It had hardly turned a wheel since the
previous box had been replaced.
Ring any bells?
I thought it might be the fork on the reverse gear wearing out. I drained
the box (lots of bronze iddy-biddy flakes) and got under it for a look-see.
I moved the gearstick into reverse and noted the position of the little bolt
that holds the reverse fork onto the shift inside the box. If you look
directly up into the drain plug hole, you can see it central when in neutral
and then 2/3 obscured when the car is fully in reverse gear. On this one,
it was only 1/3 obscured.
I opened up a dead Minor box that lay in the garage. It had been steam
cleaned inside and out some months previously. I did the same operation on
it and noticed that the fork itself was barely worn, although the gears were
knackered. Having worked out where to feel for any play in the fork on the
Midget, I tried again. This time the gearstick was out of the car and I
was able to push the little bolt further back from the drain plug hole. I
decided there was no extra play and no differences in the mechanism that
might explain the lack of range of movement of the Midget reverse
fork.......until.....I lay the Minor gearstick next to the Midget one.
It seems the ball on the bottom end of the minor stick is a couple of
millimetres further away from the centre of the large ball that it all
swivels around. The extra length allows the fork to be pushed further along
the shift inside the box and lets the reverse gear get engaged over more of
its length. By using the nice chromed gearstick that was on the Midget
originally a smoothcase???) the reverse was only half engaged when the
lever was at full reverse position.
So I put the Minor gearstick in and the whole thing worked perfectly.
|