Morning

the broken needle bearing cased havoc.  Look like the there’s high in the middle where I draw a black line.

Few other questions.

 

1. my trans doesn’t have the oil gutter. Should I put one in?

2. Only able to find cluster hex nut https://www.transmissionpartsdistributors.com/fs5w71-transmission-nut-for-cluster-shaft-fits-86-nissan-nis-220/?gclid=EAIaIQobChMIkavUq9ag9wIVPg2tBh3-hAYFEAQYAiABEgJR4vD_BwE

 

3. it sounds stupid to reuse the main shaft nut if I cannot find replacement.

 

both hex nuts are normal, right hand threaded 

On 4/9/2022 at 10:47 AM, EuroDat said:

The hub broke very clean. My best geuss is it happened when you went from forth back to third. The damage was done when you was in forth, but the pieces stayed in place until the gear sleeve slid over to third. It's an interesting failure, one I have not yet seen in person.

And now why did the hub go through so much stress? It could be a worn needle bearing between the input and main shafts causing mis-alignment between the shafts. It would be interesting to see how much wear on the needle bearing and surfaces.

Looks like the needle bearing was the cause of yhe hub failure. Not much help now, but intrresting to know what caused the hub to fail.

Why the needle roller cage failed? Could have been a assemble fault. The rest of the transmission looks to good to be normal wear and tear on the needle bearing. Maybe someone tapped the input shaft in with a hammer.

I am with John @Av8ferg on this one. Now is the time to look for another transmission.

4 hours ago, 240zadmire said:

Few other questions.

 

1. my trans doesn’t have the oil gutter. Should I put one in?

2. Only able to find cluster hex nut https://www.transmissionpartsdistributors.com/fs5w71-transmission-nut-for-cluster-shaft-fits-86-nissan-nis-220/?gclid=EAIaIQobChMIkavUq9ag9wIVPg2tBh3-hAYFEAQYAiABEgJR4vD_BwE

 

3. it sounds stupid to reuse the main shaft nut if I cannot find replacement.

 

both hex nuts are normal, right hand threaded 

1. YES. You should fit a gutter.

2. ?

3. Not sure which transmission you have. Have s look in the document in link.

Not sure if this transmission is worth rebuilding with the costs of a new input shaft, main shaft, 3rd/4th hub and bearing kit. Might be better to find snother and pick the best parts of the two and add a bearing kit.

 

I believe the 27mm RH thread nut is NLA. There were a few offered here on the site by members that had some machined up

Yes on the gutter

I think the others are probably right. A lot of damaged parts in that case

EuroDat is an excellent source of information on Datsun transmissions especially. I would give his advice a lot of consideration!!

You could reuse the nut if you didn't destroy it when removing it.  Just peen over a different spot or use red Loctite.

You said that you have the early 5 speed, so a 4 speed should have most of the parts that you need to combine with what you have to make one good 5 speed, as suggested earlier.  People have 4 speeds sitting in their garage as spares after a 5 speed swap.

Is the main shaft the same in the 4 speed?

carpartsmanual says they are.  EuroDat's list probably also.

Edit - I screwed up here and missed a "4".  Sorry about that.  They are not the same.

http://www.carpartsmanual.com/datsun/Z-1969-1978/power-train/transmission-gears/4-speed/from-sep-71/25

http://www.carpartsmanual.com/datsun/Z-1969-1978/power-train/transmission-gears/5-speed/41

Edited April 20, 20222 yr by Zed Head

Thats what I fear the transmission is unsalvageable…. The most damage is the main shaft’s end where the pin bearing caused havoc.  I use 500 grits and it feel reasonably smooth.   The synchro hub is ordered and on its way.  

I see quite a few 4 speed around but I’m not sure if the main shaft is compatible.

 

thanks for all great suggestions. I will keep working at it.  Stay tune 

10 minutes ago, 240zadmire said:

Thats what I fear the transmission is unsalvageable….

I see quite a few 4 speed around but I’m not sure if the main shaft is compatible.

It's a collection of parts.  The fact that you had a very odd failure actually works in your favor.

Edited April 20, 20222 yr by Zed Head

Now I’m contemplating to wether to invest in the ‘82 71C or to source a donor and make this existing 71B work.

 

if I choose to keep the 71B as backup when the donor parts come along, what are the challenges of the 71C?  I mean, look at the diagrams and discussions, seem like 71C is beefier in term of gears.  Most if not all bearings should be the same sizes.  What about cluster and main shaft hex nuts? Are they all left-handed or normal, right-handed.  
 

I learn from my 71B not rebuild when the car was apart, there’s a guy selling 71C, pretty penny, $1000.  If I buy that, I’m going to rebuild it.  What are your thoughts?

 

regards 

If Zed is correct and the 4 speed shares the parts you need. I would try to source a cheap 4 speed and cannibalize it. I wouldn't worry about power handling unless you plan to make some serious upgrades