Hello lovely people,

i search for an older thread as someone had already done some experiments with the FS5C71B europe transmisison.

I drive an 73 240z from Europoe and my transmission 5th gear pops out. ( its not just only the main shaft nut whicht needs to be tighten)

If i tighten the mainshaft nut - It seems to be that the last washer on the mainshaft is to tight so the gears get blocked.

And someone was able to create a small brass spacer and placed it between the last washer and the main shaft gear bushing.

If someone finds this post and or knows the person who has done that - that would be nice.

He also postet a lot of images of this rebuild - if that helps.

I would love to understand if the fix is still valid and if he faces some other issues.

Best Roman

Edited Tuesday at 10:55 AM2 days by wutsin

@EuroDat is the guy I'm pretty sure you're thinking of. He does some amazing things and always has great pictures to share his work.

Hey @siteunseen i already asked @EuroDat upfront befor i startet this topic - he also knows the topic and we both can not find it anymore

could it be on a different forum ? // iam pretty sure that i red about the fix here.....

Have you had the transmission apart yet?

Hey Cliff put on your Librarian Glasses and solve this one!!

8 hours ago, Zed Head said:

Have you had the transmission apart yet?

Yes one time - and then found the issue that the nut was super loose.

I tighten it but then the gap between last wascher and gear/gearbushing is too tight so it would block the gearings.

We loosen the nut just a tiny bit and then we welded the nut with a tiny spot.

All good so far but when i accelerate super hard from 120kmh to 180kmh the 5th jumps out by 140kmh or so. if i would accellerate slow to 180 - it would be no problem.

So i thought i need to investigate a bit more and then i found a thread where someone placed somewhere there a new created 0.00xx milimeter thin brass washer.

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I assume that the no. 64 is to tight to 54 and thats the reason why there is basically no gap between 55 and 64 and therefore the gear 48 is blocked.

The OLD post was around MAI 2024 still online and someone explained the same issue and postet a few pages with images and stuff he tried.

___

ill replace the transmission now with an 280zx close ratio and then ill have a look again and try to rebuild it.

On 12/16/2025 at 11:53 AM, wutsin said:

I drive an 73 240z from Europoe and my transmission 5th gear pops out. ( its not just only the main shaft nut whicht needs to be tighten)

Hi, If you have a lot of vibrations you need to solve those but if your 5th gear pops out of gear your spring(s?) in the main plate (between the 2 halves of the gearbox) are to short and have not enough pressure anymore.. I solved this by putting in a new spring or make the old spring longer with use of a side cutter pliers! Just note on a paper the length at start and make the spring a few mm longer by cracking the spring rings with the pliers, You need to cut into the air between the springrings .. sort off.. i hope you understand what i;m saying haha, let the piers do the job, do it little by little so the spring stays straight!

@siteunseen He's talking about the C not the W type gearbox, a Fs5C71B is a european ( and asian??) gearbox used in the 240z with 5 speeds.

THe C has Porsche steel synchro's and the W box has brass synchro's.

The C box is much more rare than the W box i understand..

BTW, in what country are you @wutsin It does no longer stand in your reply.. @Mike it would be handy to have the countryname in the reply's as it ones did.. :-/

@dutchzcarguy = yes its the porsche style syncro (FS5C71B) // I live in germany and the car is originally from italy

@siteunseen = ill have a look at the springs as well but 90% there are not the issue - as all gears are super nice and stiff to shift - no wobbeling and if i shift from 5 in neutral you can feel the resistance,

i think you mean this = right ? (image is not from me ) its from https://www.youtube.com/watch?v=YB_6o1De40s

1 minute ago, wutsin said:

i think you mean this = right ?

Yes! I had a long time ago a 280zx, and it kept going out of 5th gear when decellerating. i lengtened the spring (by a few mm) of the 5th gear and the problem was solved!

You live in Germany, i live in Limburg near the border of Germany! If i go 2 km to the east i'm in Germany! (Kreis Kleve!)

Maybe your in the neighberhood?