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"I concur" (what he said!)

Should've posted a comment to show appreciation. I found it very interesting also. I kept going back to see if you would show us how to put it all back together properly.

I can volunteer another box if that's what's needed

I only just read it all and I was very interested :( Good work on it though Haha

With nearly all Datsun gearboxes the numbers represent the center distance of the bearings. That's the input and lay shaft.

Nick, I sold the gearbox last year to Spike for his bakkie. Nobody was interested in the thread so I dropped it like a hot bearing.

Ver nice Build there !!

I especially like this part here... Is this Way that they came up with the name 56a? What are the two shafts that Line up here?

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So this gonna get finished don! Good read to! Wouldn't mind trying it myself as might need to rebuild my 71's a few time I dare say

As you can see, I am holding the syncro ring in place on the syncro cone. A nice even gap should be visible and when pressure is applied it should no rock or give any indication that it is bent. 100% surface contact is what you want. Note the gap, The service manual of the gearbox should give you an idea of what the tolerence should be, smaller boxs like this are usually around 0.7mm to 0.9mm, but as long as the ring grips firmly to the cone it will work o.k.




I'm checking the gap and I have found the measurement to be 0.83mm. There are no serious signs of wear and everything looks and feels good. All 4 gears vary but are consistent within 0.01mm. Very nice. I usually see 2nd wear fastest and I would be suspect of anything measuring below 0.6mm.

All cleaned up and ready for inspection. A good starting point is if your gearbox has a magnet, see what is stuck to it. It will give you a good indication of what you expect to find.




Bearing inspection is fairly obvious, and in my opinion, they dont need to be replaced for the hell of it, sometimes a repair can be just fine. But for the sake of $70 odd I'm not going to bother with an inspection, I'm just replacing them all. After all, i am rebuilding it, not repairing it.

The gear dogs and leads should be burr free and have nice points, not rounded shoulders.

Now that 1st gear is off, the bearing and bearing sleeve are exposed. Pressure on the selector hub will coax the sleeve off. Once again, everything gets marked with the pen, and later engraved.




2nd gear now falls off and you have a dissassembled gearbox ready for cleaning and inspection. Let the cleanup begin.... Sh!t!!! I forgot how I hate this part.




I should point out that it took approximately 1.5 hours to dissassemble the gearbox entirely without encountering any problems.

Input shaft off. So I don't mix up the synchro rings I will initially mark them with a pen ao as not to mix them up. The input shaft on these models does not use a circlip to retain the bearing, so to prevent the input shaft bottoming out it uses a thrust washer in between the selector hub and input shaft. A single 3mm ball locates the thrust washer. Budget and efficient old school stuff really. Not high torque stuff really.




No circlip retains the 3/4 selector hub oddly enough. Once the 3mm ball is removed the hub will come off and so will 3rd gear and bearing. I also mark the hub, and later engrave it so that it all goes back together in the exact same way.




Now the press sissors go onto the rear bearing for safe removal.




And once removed will expose 1st gear. Behind the bearing is a thrust washer which also doubles as a gear height shim.