1978 280z Transmission noise in 1st & 2nd gear, metal shavings!

[Ownallday]

Okay so my 1978 280z has a 5 speed transmission (not sure what year), has always made noise in 1st and 2nd gear when not pressing on the throttle (kinda soundings a little like a grinding and maybe whining noise). When the clutch is pressed in, no noise, if I am on throttle, no noise. Only makes noise 1st and 2nd gear when coasting (no throttle applied) and you can kinda feel it not coasting smoothly but once again only in these two gears. Based on the symptoms and pictures I provided, are my bearings or synchros bad? Asking before I pull trans for rebuild with the rebuild kit from zcardepot or if I should just buy a new trans since I am unsure if a rebuild will solve this issue

 

[EuroDat]

That is a piece of bearing cage on the drain plug magnet. Most probably from the counter shaft (sometimes called cluster shaft) bearing in the adapter plate. 

If you want to rebuild the transmission, I would strongly advise dismantling it first to asses the condition. A rebuild kit could be enough to restore it to good working condition, but it might have a lot of other damage where a replacement transmission would be the better option.

If you want a parts list, see link in downloads section.

 

 

[Dave WM]

Yep bearing cage for sure. Rebuilding is not that hard to do, helps to have a press and some pullers but as EuroD mentioned may as well open and examine before buying a kit. I am always amazed at stories like this, trans works even with all the carnage in the case. I guess the bits tend to fall down and not enough wave action to drag them up into the gears. As long as the balls have stayed inside the bearing races it seems damage does not happen.

Edited August 2, 2020 by Dave WM

[Zed Head]

New bearings will probably solve the problem.  If it shifts well, you might not even want to install new synchros.  People have reported that the aftermarket synchros are not of high quality.  And the Nissan synchros, if you can find them, are very expensive.

There are few rebuilding threads on the site.  EuroDat, Dave WM, and I think zKars have all dived deeply.  Some of the other members also.  There are some tricks and special tools needed.  You'll have to tear it all the way down,

[Mark Maras]

 Pics of the tear down would be great.

[Ownallday]

7 hours ago, EuroDat said:

That is a piece of bearing cage on the drain plug magnet. Most probably from the counter shaft (sometimes called cluster shaft) bearing in the adapter plate. 

If you want to rebuild the transmission, I would strongly advise dismantling it first to asses the condition. A rebuild kit could be enough to restore it to good working condition, but it might have a lot of other damage where a replacement transmission would be the better option.

If you want a parts list, see link in downloads section.

 

Thank you, had a feeling it was a bearing, do you know if the kit from zcardepot comes with this specific bearing? I am okay with doing a trans rebuild and testing my luck before purchasing a new 5 speed, mainly because I will not able to do the rebuild at home.

[Ownallday]

4 hours ago, Dave WM said:

Yep bearing cage for sure. Rebuilding is not that hard to do, helps to have a press and some pullers but as EuroD mentioned may as well open and examine before buying a kit. I am always amazed at stories like this, trans works even with all the carnage in the case. I guess the bits tend to fall down and not enough wave action to drag them up into the gears. As long as the balls have stayed inside the bearing races it seems damage does not happen.

Good to have a second opinion, will the kit from zcardepot have the bearing cage, unsure as they don't state it. I will being doing the rebuild at my job, I work as a technician at toyota so I should have all the tools needed as I don't have the luxury of being able to do a job like this at home so work is my only option which limits me a little. I am fine with taking the risk on rebuilding without inspecting. I am very shocked my car still drives the way it does, hell I have even ripped it many times in the canyons.

13 minutes ago, Mark Maras said:

 Pics of the tear down would be great.

I will update this post or make a new post in the future when I get to that point

[Zed Head]

5 minutes ago, Ownallday said:

will the kit from zcardepot have the bearing cage,

The "cage" is part of the bearing assembly.  Typically just called the "bearing".  When you say bearing you're talking about the balls and races and cage (AKA retainer).

Basically your "bearing" is falling apart.  Dave WM had a similar issue and rebuilt his many years ago.

https://en.wikipedia.org/wiki/Ball_bearing#:~:text=Assembly is completed by fitting,only to maintain ball position.

Edited August 2, 2020 by Zed Head

[Ownallday]

28 minutes ago, Zed Head said:

New bearings will probably solve the problem.  If it shifts well, you might not even want to install new synchros.  People have reported that the aftermarket synchros are not of high quality.  And the Nissan synchros, if you can find them, are very expensive.

There are few rebuilding threads on the site.  EuroDat, Dave WM, and I think zKars have all dived deeply.  Some of the other members also.  There are some tricks and special tools needed.  You'll have to tear it all the way down,

Interesting, I guess when it comes down to inspection I will inspect the synchros and see if they need replacing based on condition. The car shifts like a champ in all gears but reverse can be a little stubborn sometimes. I give those threads a look at. I will be doing the rebuild at my job at Toyota so I believe I will have all the tools needed, any specific special tools?

[Zed Head]

 

[Dave WM]

if its not having issues with shifting the sychros (anti baulk rings iirc) are prob ok. You can tell a lot after its apart. there are specs for how to tell, and you can test by seeing how well the "grab" and lock onto the cones of the gears.
Reverse is not like the others, its not constantly meshed. It relies on the shape of the teeth to allow it to mesh with the reverse idler, so every now and then you could have those two gears line up perfectly tooth to tooth, will not engage. just ease off the clutch in N and try again.

[EuroDat]

21 hours ago, Ownallday said:

Thank you, had a feeling it was a bearing, do you know if the kit from zcardepot comes with this specific bearing? I am okay with doing a trans rebuild and testing my luck before purchasing a new 5 speed, mainly because I will not able to do the rebuild at home.

The standard kits with have the two bearing in the adapter plate. Those two bearings are generally the ones that give most of the problem.

Note: Some kits comes with a larger front counter shaft bearing for the 71C transmission. All the synchos and bearings, with exception of the front counter shaft bearing are the same for the 71B and 300ZX, 200SX 71C transmissions.