Good day, 

for some time I am trying to understand a transmission noise that is bothering me. As you can hear in the video the gearknob is transmitting some buzzing noise which can be altered by holding the hand in front of the knob to act like a kind of sound box. You can best hear it toward the end of the video.

I read about the buzzing problem related to worn gearstick bushing and ordered a new set of oem bushings, cup and pin. After the change the noise persisted I also changed the old after market wood knob to an oem rubber one. Also no change. Next step was to check for wear marks on the stick (read it in some other post). I found some small ones, ground the stick a little bit so it wouldn't touch anymore but still no luck with the noise. As far as I can tell the transmission is a wide ratio FS5W71B (two ears at the extension housing). Oil is one year old Redline's MT-90. There was a little bit of 'metal dust' on the plug.

I wouldn't call the noise a grinding noise. It is more 'fine grained' if you can call it like that, more like a buzzing. Like a very fine sandpaper on a piece of metal. It happens in all the gears and gets worse with speed. In the video i am driving between 75 and 70mph above that it gets even louder and becomes more like a hum.

It would be awesome to hear your opinion on this one. Especially, if this is something to be concerned of or maybe even normal (don't have much experience with old transmissions).
 
Three things came to my mind: 

1. something related to the clutch/flywheel?
2. worn bearing in the transmission?
3. propeller shaft (u-joints, unbalanced)? 

I definetly have to drop the box in the future, because of some oil leak at the striking rod (leaks at the plug in the rear). So it would be nice to know if I should replace some parts to fix the noise in the process. 

 

Before someone asks - the butler creek flip up is covering some AFR display in case I don't want to see it.
 

Not to hijack the thread but I also had a shifter rattle (that never really left)... See thread

Last week I noticed that the gearbox makes clicking sounds (like a bad bearing) when the clutch is not depressed, when the clutch is depressed the noise goes away. I think I need to pull the gearbox apart for a rebuild...

In your video I a can hear the vibration through your hand, it reminds me of what mine was doing before the clicking started.

I'm  spit balling here, sorry but it might be something too look at. My shift lever was hitting the transmission "cup" and causing mine to pop out of gear. It was noisy also.

 

 

I wouldn't think reason #1 or #3 as likely culprits.

I would suspect internal wear...

Can you feel the vibration anywhere else? Seat, console, or is it isolated to the shifter?

 

Sounds like you have a failing main shaft adapter plate bearing. Typical when you lightly push the gear stick further into the selected gear. You are then pushing on the thrust function of the center bearing. The center bearing is a typical bearing failure in these transmisions.

The gear knob generaly moves vertically with unbalanced propeller shaft vibrations. If you hold your finger just above the knob, it should tap your finger in the same frequentcy of the sound. That is because the transmission mount is more flexible in the vertical axis among other things.

The oil leak is a lip seal in the selector rod. Size 14/20x4.2mm. Nissan partnr 32858-U6702.

Both will need dismantling the transmission. Good time to give it a bearing kit and check for other worn parts.

1 hour ago, Mark Maras said:

Can you feel the vibration anywhere else? Seat, console, or is it isolated to the shifter?

 

isolated to the shifter.

 

1 hour ago, EuroDat said:

Sounds like you have a failing main shaft adapter plate bearing. Typical when you lightly push the gear stick further into the selected gear. You are then pushing on the thrust function of the center bearing. The center bearing is a typical bearing failure in these transmisions.

The gear knob generaly moves vertically with unbalanced propeller shaft vibrations. If you hold your finger just above the knob, it should tap your finger in the same frequentcy of the sound. That is because the transmission mount is more flexible in the vertical axis among other things.

The oil leak is a lip seal in the selector rod. Size 14/20x4.2mm. Nissan partnr 32858-U6702.

Both will need dismantling the transmission. Good time to give it a bearing kit and check for other worn parts.

If I understand you correctly by pushing further into the gear the noise should get louder? In the video I tried to not move the stick but only touch it to better caught the sound on camera.

I saw the process of replacing the o ring in some other thread and was amazed that one has to dismantle the whole afair to reach it. 

Is there a recommended bearing kit for these transmissions?

It really depends on the damage in the bearing itself. It dosn't sound like the cage (metal frame in the bearing that holds the balls evenly speced) has collapsed.

More like the bearing is worn. If you look inside a bearing it should have shiny contact surfaces. In this case they would be dull and light grey in colour. This is caused by low oil level or contaminated oil not being changed in time. The other bearing that suffers in this case is the neddle bearing between the input shaft and main shaft.

 

Buying an aftermarket kit is going to be fun. All the miss information possible. Really.....

The 71C bearing kits are easy to find. Warning nothing after 1988. The early 71C kits will fit the 280Z. True, but the front counter shaft bearing in your transmission is 56mm OD. These kits supply the 62mm OD bearing for the FS5W71C. You can find the 71C kits easily and then order a separate 63/22N C3 bearing (63/22N).

The kit for the 280Z is the BK-104WS with the 56mm bearing and getting harder to find. A lot just say the 71C is a FS5W71 kit that fits all.

This is a 71B kit. https://transpartswarehouse.com/bk104ws-nissan-fs5w71c-manual-transmission-rebuild-kit-1980-1984.html

They say 60mm bearing in description, but it is a 56mm bearing. Idiots Even call it a 71C kit.

 

Here is an example of the 71C kit. The kit mostly use codes like BK-133WS

https://www.4ws.com/product/fs5w71-transmission-bearing-seal-kit-nissan-200sx-280z-280zx-maxima-610-620-720-810-5-speed

 

BTW. The neddle bearing is for the input shaft - main shaft and NOT the reverse idler like some people use it. That bearing generally doesn't wear much.

You could also look for the genuine Nachi bearings.

See my rebuild list I made when doing my transmission.

 

Oh and good luck. If you have any question, just shoot.

Thanks for the info. I guess it is time to start the planning phase - what is needed and how to get it to Europe. 

They can last a long time before they are unusable.  There are threads on the forum from people who took theirs apart and found signs of destruction even though the transmission still worked properly.  Strips of bearing cage/retainer, loose ball bearings in the bottom of the transmission.  Still worked.

51 minutes ago, Zed Head said:

They can last a long time before they are unusable.  There are threads on the forum from people who took theirs apart and found signs of destruction even though the transmission still worked properly.  Strips of bearing cage/retainer, loose ball bearings in the bottom of the transmission.  Still worked.

Yes, I read some of those threads. Especially, the one with the mostly missing bearing was impressive. I am just hoping that I can postpone the repair for a little while. I Don't want to miss out on the good weather days this year. 

Each case is different, obviously…. If I were you, I would take it apart and buy the rebuild kit to replace all bearing and seals, especially this transmission hasn’t rebuild after 40 years.  In my case, the rebuild cost less than $100 compare to toasted the whole transmission.  Good luck.