5 Speed Transmission inspection and possible rebuild.

[Mark Maras]

Looks very good. I'd say it's been apart twice before judging by the staked nuts. Take a good look at the brass synchro rings. The pointy end of the teeth should come to a sharp edge rather than be rounded over.

[Av8ferg]

Thanks for the feedback. Here’s a close up of one of the synchros. They all look about the same.




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[Zed Head]

There are a few other things you can check without taking it apart.  The roll pins that hold the shift fork to the shaft.  Sometimes they can wear or break or wallow out their holes.  Make sure the forks are tight on the shafts.

I looked at your video but didn't see the oil gutter.  If it's gone the reverse gear or maybe the idler will get dry. 

Check the straight cut reverse gears for chips.  They don't really matter but it gives an idea of abuse.  

The gutter is a mmysterious thing, it's only shown in the 4 speed drawing but it exists on all of them. It's a trough that catches oil and transfers it through the adapter plate.

[Av8ferg]

Thanks ZH. I will check all that out. What the best way to clean up some residual debris I see in between the gears and along the shaft? High pressure air? I guess using something like carb cleaner my not be a good idea due to removing oil but I don’t know. As all as you re-lube it all well it might be fine. It will sit open for about a week until the cases are blasted clean. I’m ordering a new throw out bear release that attaches to the fork. Since I don’t have a press I’m buying it already built. RockAuto sells them for about $39.


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[EuroDat]

Looks like the bearing have been cheaply replaced. Why I say cheaply? They reused the nuts. I wonder if they changed any of the seal while they were at it.

It looks very good from the video. Reverse gear is still in good condidtion (the idler spur gear), but that is generally due to the reverse lock out device helps prevent accidently hitting reverse on change down in the close ratio transmissions.

You can take some measurements without striping it down any further. It will take a bit of fiddling, but it can be check without dismantling. That will give you a better idea of the condition.

Baulk rings: The grooves inside the baulk ring do all the work getting the gears to similar speeds. The teeth on the outside of the baulk ring do the last step by aligning the teeth. It the grooves are worn down, the gears will be at different speeds and the teeeth will grind. That is the wear that Mark is talking about, but it started at the worn grooves.

 

Gear end play: The next thing you can check is gear end play. If you are driving and take your foot the throttle and the transmission goes clunk. That can be other things like the diff, but it can also come from the gears snapping back.

While you are in the transmission, I would put changing all the seals and the oil gutter ZH mentioned on my priority list. Those oil gutters can get damaged during rebuilds and can take so much benbing back before they break off. They only cost 3 or 4 dollars.

I have a list of all the seals with Nissan part numbers and sizes so you can source them locally.

The check springs in the selectors would be nice to change now.

[EuroDat]

Here is a list of the parts when I did the close ratio I had. The seals are what you want. The seals, springs and oil gutter are listed in their sections according to the parts manual cross section drawings.

I think I will clean up that list and post it in the technical articles later.

 

Tranny_Rebuild_FEB2012.pdf

[Av8ferg]

Hey, thanks for all this information. I’ll start going through all those procedures and inspection points. Lots of information to digest especially when I really don’t understand how this thing really works. This is how you expand your knowledge; by diving in and learning. Sure helps to have some experts on this forum to keep you from making some fatal errors.
Thanks for the parts list. I was looking online and I’m hoping most are easily sourced. Will start ordering some of that stuff. My hope is I don’t have to do any further work other than the aforementioned.


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[EuroDat]

Visually it looks in good order and it looks like someone did the bearings in the past.

Seals: If you buy aftermarket seals (o-rings and lip seals) remember to ask for NBR or Viton rubber. Sometimes they have EPDM.

Check springs: I don't know if you can still get the check springs, but they do make a difference in the selsctor movement. My old ones were about 2mm shorter than the new ones and lost a lot of tension. They gave it that kind of click sensation when the shifter goes into the gear.

If you can't get the springs, you can try a couple of small washers with the same outside diameter behind the old springs to increase the pressure. Be carefull not to go overboard or the springs could bind and loose function.

[Dave WM]

looks like the adapter plate counter shaft bearing has a seal on it. I don't think that is a good idea, pretty sure that is supposed to be an open bearing. You would want gear oil to freely flow through out the trans. I don't know if I would tear it down just to replace that, or try to pick it out, or just leave it. the trans looks good after all.

[Av8ferg]

On 5/23/2020 at 4:20 PM, Zed Head said:

Timing...

Be careful with the oil gutter on the other side.  It gets bent often.

About this oil gutter.  I don’t have one on my transmission.   I looked at the FSM and it appears that the 4 speed exploded view show an oil gutter but the 5 speed does not.  I also looked around and could fin one available, for sale.  Are they hard to find,  and are we sure the 5 speed ZX transmissions had them?  See attached pics from FSM. 
 

 

[Zed Head]

grannkyknot has also rebuilt a 5 speed.  EuroDat posted some pictures in his thread.

I opened up the 1982 FSM and found a similar issue where they don't show it in the diagram but do describe it in the reassembly text.  It's an odd little chunk of folded stamped metal.  You could probably make your own pretty easily.  I don't think that there's much engineering in it.

 

 

Edited May 25, 2020 by Zed Head

[zKars]

19 hours ago, Dave WM said:

looks like the adapter plate counter shaft bearing has a seal on it. I don't think that is a good idea, pretty sure that is supposed to be an open bearing. You would want gear oil to freely flow through out the trans. I don't know if I would tear it down just to replace that, or try to pick it out, or just leave it. the trans looks good after all.

I've had bearing come with those seals. Absolutely remove the seal. Just pick them out, they are not held in tightly at all.