Well, due to popular demand, I'll take you all through the ins and outs of a 56A 4 speed manual gearbox. This is a project that I have no particular use for but it does please me somewhat to help out where I can for the greater good of the Datsun community.

'The Greater Good'

If there are any questions feel free to ask, and remember, as Mr Garrison said, 'There are no stupid questions, only stupid people.'

First off, as I had none lying around, I sought a suitable donor gearbox for the project, which has it's own interesting tale of lust and seduction. Then off to the bench it went. I was assured that it would be good to go in the car as is, but on visual inspection I noticed it had a broken breather and appeared to have a weep from the gearshift quadrant. So onto the bench it went.




So first I upended the box to make sure it was not full of oil. A must if you don't want to clean up a dirty filthy mess, then set about removing the switches, quadrant detent and shifter pin.







Out with the bolts that secure the extension housing to the front case through the sandwich plate and seting the gearbox upright then moving the quadrant to the right hand side of the gearbox moving the selector finger out of the selector gate to allow the rear case to be removed safely. A tap on the gasket face with a nylon hammer to break the siliclne seal will make life a bit easier.







I must point out at this stage that when you do take apart anything with an alloy surface that you should NEVER use a steel hammer of any kind. Nor a screwdriver. That is a BIG NO NO...

Cool, another one
I love these, learning time!

yay do mine

Thanks Don, about 4 years too late for my poor little 56 box I raped. On the plus I have a fool proof clutch aligning tool for my rebuilds

I'm sorry to hear that you raped your gearbox. I hope your dick is o.k....

Another sharp tap should safely seperate the front case. Here's a tip. A firm precise strike with a hammer beats a massive hard random hit any time. So hitting it harder isn;t always better. I choose a nice solid part using the gasket face as the center line and while i hit it a couple of times I listen for the change in sound from sharp 'thwack' sort of noise to a hollow noise that indicates that the alloy has seperated. You need to do it to at least 3 points on the surface to make sure the sealant has let go all around. I'm not left handed with the hammer, just right handed with a camera...




The front case can come off.

On the 56A the input cover can remain on. There is no circlip to retain the front bearing. The photo's I took of the front cover coming off turned out crap. But it will not affect the outcome of the gearbox.

Once the front case is off the gearset can be placed on the bench and get ready for the vice.




In a previous thread I mentioned that the series rating on a gearbox relates to it's centerline distance. Here is the proof.

oh there is hope for my 7 4speeds.love you work.

lol Don

do you put two pieces of hardwood in the vise before clamping the sandwich plate?

I don't use hardwood DD, but I do use soft jaws in the vice. Which is just alloy right angle and it use a rag for safe keeping. Even on a steel sandwich plate I use just the alloy. As long as the surface you are clamping is harder than the jaws it will be safe.

It is always a good idea to make a list of things that you notice that may require some attention. That way things don't slip your mind later on. If there was a specific problem with the box, that would be at the top of the list. I noticed a broken breather and a weep from the gearshift quadrant that I thought will require some attention.




Into the vice it goes, using the dowell as a stop. I have the alloy jaws in place along with a rag to absorb any mischief that may occur.




First thing to dismantle is the reverse lever. I removed the roll pin but when I removed the fork, at the last moment the rod came out with the fork. Not a big deal, but it could have been prevented if I had selected 3rd gear which would have locked the reverse rod in place with the interlocks.




Now I can remove the mainshaft reverse gear, first I remove the circlip and the spring loaded washer that retain it.




Now I can remove the other rods and forks, paying attention to where they go. At this stage there is no need to remove the reverse spline gear as it will pass safely through the sandwich plate and I'll take it off later.

Don are the forks steel on the 56a or alloy like the 71b?