Sideshift gearbox question

So the OD got rebuilt for the tri carb today and refitted with the gearbox and onto the engine . I then removed the drain plug on the gearbox to drain any left over dregs of oil .....three ball bearings fall out 5/16” diameter.
Well after a lot of words which cant be printed I did some looking in the trusty Haynes manual and the pics show three balls under the shift rod springs . So off comes the side cover and sure enough springs and balls of the exact same size are all in place .
The plot thickens .....I retrieved the broken off section of shift lever split bushing which was in the bottom of the gearbox and then take a second look in the Haynes book .
Look at the pic attached it shows two balls without any reference number that look like they should go in where the split gearshift bushing goes .
Any other ideas where the “mystery balls “ go and whats the purpose of the balls below the bushing .
I can possible see the purpose of one so the tip of the gear shift lever has something to roll on . But two ??
Help appreciated

Ok so more investigation and studying of drawings and manual its the interlocking balls from the selector shafts . They must have dropped out of place when I had the OD/bellhousing/gearbox all separated .
I guess I must have moved the selector rods back too far at some point and they fell into the bowels of the gearbox .
Soooooo I guess its all coming apart again unless someone has some other ideas .
I did manage to remove the plug at the front left corner of the gearbox so I guess the balls drop in from the top as you install the selector shafts ?

I believe you can just remove the side plate to replace them.

The sprung balls held by the side cover can be simply removed and installed. The other two have to be installed vertically between the shifting shafts, which requires the top two to be slid out of position.

There are only 2 of the balls that go in from the top--in a sideshift, from the side in a top loader--and you mentioned you found 3. Have you figured out where the third goes? These prevent the box from trying to engage two gears at the same time, in which case the 'car will remain stationary' as amusingly noted by Magnus Karlsson:

https://youtu.be/9rz6b8ZWXfc

BTW, 5/16" ball bearings are used in other places; the place that comes to mind is the seat sliders. I lost one when repairing one of the sliders, ordered a bunch from a ball bearing 'specialty' site and threw the spares in a parts bin.

I spent some time playing with the gearbox on the weekend .
All three balls behind the springs are there and I tried to manually shift two gears at once and I couldnt do it which indicates to me that the balls between the selectors are still in place .
Its also impossible for the balls to drop out as the selector shafts dont have enough rear movement with the OD removed .for them to drop out unless you remove the selector forks .
So I have concluded that they were lost in there from a PO and its carry on with reassembly .

If you go to the Moss illustration for gearbox parts, you will see part number 329-520. Checking the "where used" tab, the same ball could be from a sliding hub in the gearbox. They can easily pop out when things are disassembled.
Bob

British_Recovery said:

If you go to the Moss illustration for gearbox parts, you will see part number 329-520. Checking the "where used" tab, the same ball could be from a sliding hub in the gearbox. They can easily pop out when things are disassembled.
Bob

Click to expand...

Sliding hub ??? . Part index number

If you refer to your thumbnail illustration from the factory manual, look at part number 4 -"synchronizer ball".
Moss "internal gearbox 4 speed" - see number 27 and 42.

British_Recovery said:

If you go to the Moss illustration for gearbox parts, you will see part number 329-520. Checking the "where used" tab, the same ball could be from a sliding hub in the gearbox. They can easily pop out when things are disassembled.
Bob

Click to expand...

That's the most plausible explanation so far. Had the gearbox just been dis/assembled and not run? If the balls had been run the gearbox would have made a noise--though I can't 'picture' it--and would have been pretty well mangled (along with a gear tooth or two).

That, and three balls are used in the sliding hubs. Have you tried to shift the box on the bench?

As already stated the gearbox will shift , however as pointed out there are balls in the sliding hub assemblies which according to my British car nut brother who has played with these things on numerous occasions .
If the thrust washers are put in incorrectly they the balls can pop out as you shift .
The gearbox was fully assembled when I bought this “box car” project so who knows what was done previously .
so basically its all coming apart for investigation purposes