1977, 280z with FS5W71B transmission

[240zadmire]

Greeting folks,

 

I believe my 5-speed transmission is version FS5W71B as it has 2 prongs for the exhaust mounts.

I usually do a 40 miles drive on the weekend.  Yesterday, when I shift into 2nd gear, I felt hard "jolt" as if i ran over the cow or hit a big rock under the oil pant.  I can definitely felt that something is wrong with the transmission. 

I'm not sure if I describe what I felt correctly ... normally, if the clutch pedal is not depressed, the transmission connects to the flywheel directly, you felt/and hear the gentle sound like when you biking the bike down hill without you pedal-ling it, the sound from the gear make a small, pleasant sound.   But after the "jolt" felt, the sound is much noticeable.  But when depress the clutch, it's as quiet a the mouse.  Does that make sense???!!!

I'm pretty confident there is something wrong with the transmission.  The bearings might be gone.  What do you guys thing?  Any suggestion where should I diagnose the problem?

 

regards,

 

 

[Mark Maras]

 Is it in any gear, or in neutral, when you're depressing the clutch and it goes silent? The jolt, I suspect, was a portion of a gear tooth, my first guess would be the input shaft gear. I hope I'm wrong.

[240zadmire]

Hi Mark,

Neutral or any gear, the noise goes silent when depressing the clutch.

I'm still able to shift to any gear and driving without any problem.

I fear I have to disassemble the transmission to know what is really wrong with it.  I've been searching online to see what is the best rebuild kit for the job ... seem like there are a lot of info out there.  I'm still not sure which kit fit the bill. 

 

regards

 

 

[Zed Head]

I'm going to guess that the jolt was a ball cage/retainer on one of the adapter plate bearings.  People often find pieces of the retainer when they do a fluid change.

The transmissions seem to just keep going though, it's amazing how destroyed they can look but still do just fine when new parts are installed.

Draining the fluid will probably tell you something.  Look for metal shavings and flat pieces of metal.

https://www.researchgate.net/figure/Main-parts-of-ball-bearing_fig1_289540744

[EuroDat]

Sounds like you have the wide ratio FS5W71B which is the original version 5 speed for the 280Z.

The test you did with the clutch disengaged (depressed) tells you your problem is inside the transmission.

You can determine if your problem is in the cluster shaft or main shaft by driving through all the gears. If a bearing in the cluster shaft is damaged it will be noticable in all the gears except forth gear.

The bearings that tend to go first are the bearings in the adapter plate in the centre of the transmission. If could be the adapter plate bearing for the cluster shaft or the main shaft.

Check for metal in the oil.

[240zadmire]

Gents and ladies

 

Bad news.  Drained the oil and 2 small metal derbies stuck to the drain bolt magnet.  The other 2 pieces of gears were near the drain hole.  I was able to pull them out using my pinky.  The 2 pieces gears look like a 3-pieces as their ends look cleanly cut.  Take a look at the photos.

 

what am I up to? The trans is totally toasted or still salvageable?  It’ll take me at least another week to pull it off the car.

 

 

regards

 

[Zed Head]

@EuroDat will have a better idea but it looks like the remains of a synchronizer/baulk ring, but kind of different.  Can you take a picture of the teeth on the parts?  They look wide.  The other magnetic parts might be bearing parts, which might have caused the synchro ring failure.

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

https://www.nissanpartsdeal.com/parts/nissan-ring-baulk~32604-p0100.html

https://www.ebay.com/p/1529633534

https://www.nissanparts.cc/oem-parts/nissan-ring-baulk-s12-z31-720-c31-c32-d21-r31-32604p0100

[mayolives]

QUOTE: The trans is totally toasted or still salvageable?

You have a job ahead of you but you should be able to find the parts needed.  The gear box will have to be removed and pulled apart in order to know what it needs. If you are mechanically inclined there is lots of good information here on the site and at other sites that can guide you through the process.  Also, this will be a good time to replace your clutch, pressure plate, through-out bearing and rear main seal.  It's not an easy job but other than replacing your transmission with another good one, and they are becoming difficult to find, it's about your only way to get back in the seat.  

[240zadmire]

“Any thing can go wrong, will go wrong”. And this is a hell of a time to go wrong.  Spring time is here.  I planned to drive a lot but this happened…. The transmission is the only part that I didn’t rebuilt, failed after under 5K miles since I “restore” the car.  I can only hope the damage not too severe and parts are still available.  This is the wide ratio transmission built date 1977 June time frame.

 

 

[Zed Head]

Wow, that is not a synchro ring, looks more like part of a coupling hub.  I've only pondered the insides of a trashed 5 speed after I took it apart, so don't really have the memories of somebody who has rebuilt one.  Looks significant though.  You might start browsing the ads for another 5 speed, just in case.  Always good to have spares.  Even a 4 speed will get you by.

[240zadmire]

I've never seen the internal transmission before ... you probably right.  Look like the hub-synchronizer for 2nd-3rd gear.

I felt the "jolt" from stop light shifting from 1st gear to 2nd gear.

It should be 3 pieces don't you think? maybe there is another one still inside the transmission? or perhaps already destroyed.

https://www.carpartsmanual.com/datsun/810-1977-1980/power-train/manual-(5-speed)/transmission-gear/5-speed/45

 

what's the 5 speed transmission goes for these day?

 

[240zadmire]

Curious, the 2 pieces broke off, how come I can still able to shift smoothly from gear to gear?