Gday fellas, i joined this forum mamy years ago and i don't think i ever posted anything.
I own a 1969 datsun 1000 2 door sedan and recently had a bit of an accident trying to rectify another issue.
I ended up sheering the flywheel straight off of the crank clean from over revving in neutral because the trottle cable got dislodged...

Anyway long story short, i've pulled the engine out and have decided to give it a long needed refresh that it deserves but i'm completely stumped by the gearbox.

It is an A12, not sure if early or late because the dizzy is located further towards the rear and it mounts directly into my 1000 without any modified mounts.

My flywheel is 270mm in diameter, and the clutch plates are 180mm in diameter.

The gearbox has a different release lever to every other A series gearbox i've seen online and i can't seem to identify it.

The only markings on the box itself are the number 3 on it's own machine printed, and what looks like human writing (not sure how they are raised lines) reading 4-6-20.

I've attached 2 pictures indicating the lever and the numbers.

Attach file:

---

  20241001_192550.jpg (140.51 KB)

I've figured out so far that the gearbox is the original 1000 box, and the flywheel is in yhe ballpark of 9.35kg which is meant to be the stock weight of a 1200 flywheel.
I've read that a stock 1200 flywheel doesn't fit the 1000 gearbox without modification, but it doesn't look like it has any modification at all.

The input shaft to this little a10 gearbox is a little floppy and the box has been pretty noisy for as long as i've owned the car (14 years or so). I'm currently trying to decide whether i should look at rebuilding this one or upgrade to something stronger while i'm refreshing the engine.

Uf you guys have any thoughts on the matter let us know! cheers