Zx 5 speed rebuild

[EuroDat]

Btw, That punch mark is the original nissan production method. The one that now holds the nut from turning is aftermarket rebuild.

[Patcon]

45 minutes ago, EuroDat said:

Btw, That punch mark is the original nissan production method. The one that now holds the nut from turning is aftermarket rebuild.

That's what I suspected.

No concern about damaging threads if I don't deal with the rebuild punch marks and try to turn it off?

[EuroDat]

9 hours ago, Patcon said:

That's what I suspected.

No concern about damaging threads if I don't deal with the rebuild punch marks and try to turn it off?

If you don't have something suitable, I would buy an el-cheapo screwdriver and grind it down to the same width as the groove and make the point more chissel like. With that you should be able to lift up the tab on the nut just enough so it won't tear when you unscrew it.

They rearly damage the threads, but when the nut is hammered in like yours, you can tear that section out of the nut when you unscrew it. That is all you are trying to avoid with the screwdriver.

[Patcon]

7 hours ago, EuroDat said:

If you don't have something suitable, I would buy an el-cheapo screwdriver and grind it down to the same width as the groove and make the point more chissel like. With that you should be able to lift up the tab on the nut just enough so it won't tear when you unscrew it.

They rearly damage the threads, but when the nut is hammered in like yours, you can tear that section out of the nut when you unscrew it. That is all you are trying to avoid with the screwdriver.

Sorry Chas,

I was referring to the round punch mark in the nut. It seems pretty deep

[EuroDat]

55 minutes ago, Patcon said:

Sorry Chas,

I was referring to the round punch mark in the nut. It seems pretty deep

Looking at the photo more closely, it looks like the bottom of the punch mark is protuding into the shaft. I can't remember every seeing a indent other than the notch.

If there is a indent you would expect it to be exactly 180 degrees to the notch. Otherwise it would be difficult to locate where to punch it. The indent is not noticable outside the nut.

I don't think it will be a problem. It's probably sheared off when it was removed the first time round.

[Patcon]

I thought this was probably an add on from a previous rebuild to prevent the nut from unwinding.

Also, it appears from some late night ratio calculating and a Zcars technical page that this is a 1980 transmission. I have a rebuild kit that says 80-83. Are all the parts going to work? What parts do I need to verify?

http://www.zhome.com/ZCMnL/tech/GearRatios.html

1st 3.062

2nd 1.858 

3rd 1.308

4th 1.000

5th 0.773

[EuroDat]

1 hour ago, Patcon said:

I thought this was probably an add on from a previous rebuild to prevent the nut from unwinding.

Also, it appears from some late night ratio calculating and a Zcars technical page that this is a 1980 transmission. I have a rebuild kit that says 80-83. Are all the parts going to work? What parts do I need to verify?

http://www.zhome.com/ZCMnL/tech/GearRatios.html

1st 3.062

2nd 1.858 

3rd 1.308

4th 1.000

5th 0.773

They are the ratios for the 79 to 6-80 280ZX coupe early close ratio 5 speed. Strange thing is the photos in your first post show the tell tale signs of a wide ratio. I was under the belief that the early close ratio boxes had the brass synchro.

This project could shed a lot of light on this fairly rare transmission.

[Patcon]

I didn't check them all because that seemed moot. But the 5th gear and 1st gear were spot on those ratios.

We may start breaking it down next week

[Patcon]

Cody made a puller today. The OTC bearing splitter has 5/8-18 threaded holes. I went by our local fastener supply and got a section of hardened rod and some nuts and washer and a piece of flat stock from Depot. It will pull to 20"s depth...

We used a center arbor from another puller that was 5/8-18 too.

[pogden]

@Patcon, I just finished rebuilding my early FS5W71B. I encountered what I think is a discrepancy in the 79/80 FSMs, in the Manual Transmission Section. I meant to take a couple of pictures before putting the case back together so that I could post here to document the issue, but forgot. I'm hoping your transmission is in a state where you might be able to take the pictures I didn't. So, here's the thing:

When installing the OD-Reverse Synchro Hub, the 1979 FSM says the following on page MT-16: Note: Assemble OD-reverse synchronizer hub, paying attention to its direction.   It refers to the following diagram, which I believe is WRONG. The arrow should point to the right (towards the front) - the protrusion on the synchro hub butts up against the mainshaft bearing and allows the splined part of the hub to clear the bearing retainer (both of which are forward of the synchro hub). If the flat (non-protruding) part of the hub is oriented forward, the whole thing just butts against the retainer plate. 

If you could take a photo or two of the hub showing the actual orientation - maybe one showing the protrusion butting against the bearing, and another with the slider all the way forward, showing the groove in the splines facing rearward, it would be helpful for other rebuilding an early FS5W71B.

 

Edited March 26, 2021 by pogden
removed duplicate image

[Jeff Berk]

I could be wrong (keep in mind that I'm rebuilding my FS5W71B and keep having to undo what I put together) but I think you are missing a spacer (part 32624).

Just wondering, I think I read that you bought a rebuilding kit from Rock Auto. Does the input shaft bearing in your kit have a retaining ring because mine did not and I'm waiting on a new bearing that has the clip.

Edited March 27, 2021 by Jeff Berk

[pogden]

Jeff, I believe the spacer you are referring to exists in the later (close ratio) FS5W71B that was available in ~1981. The synchro design was changed, and the three-pronged spacer (32624 - I think it’s actually called an insert retainer) was part of that and it is indeed the first thing on the mainshaft behind the mainshaft bearing - on the later model transmission.

Regarding the RockAuto kit, it does not contain any retaining rings. I assume you are referring to the "main drive bearing snap ring"? I just reused mine. I hope you can find one - it seems critical to the proper axial positioning of the input shaft relative to the mainshaft. When the mainshaft, input shaft, and counter gear assemblies are all fit together and pressed into the bearings in the adapter plate, there is some fore/aft movement possible between the mainshaft and the input shaft. When I was testing the rotation/movement of the various parts, I noticed that if I pushed the input shaft firmly back against the mainshaft, the whole thing sort of "froze", but if I allowed the input shaft assembly to float forward, everything moved freely. Once everything is reinstalled in the case and the front cover is attached, I think the big snap ring keeps the right fit between the input shaft assembly and the mainshaft assembly (which is locked into place in the adapter plate by the mainshaft nut).

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Edited March 27, 2021 by pogden