5 speed will not go into reverse

[SteveB]

Ok, so my late model 1977 280Z has the original 5 speed manual.   It will not shift into reverse at all.   It will go up into 5 but not all the way so it pops out.

All other gears shift fine, no grinding, no sticking.   Everything seems fine, except shifter will not move over and into reverse. 
 

This car has been sitting for about 20 years.   So I changes the trans fluid.   It’s was dirty and had some metal shaving on the magnetic plug, but not bad and no big pieces.   Shifter was very sloppy, so I took it out, cleaned everything, put in new bushings, even the plastic bushing on the bottom of the shift rod.  Shifter is now nice and tight and I can shift thru 1-4 very smoothly.   
 

So does the trans need to be taken out and rebuilt?.  I assume gears are ok but something broke in the shifting mechanism?
 

Or can anything be done with trans in the car??
 

I’ve read to be sure clutch is fully engaging, and I believe it is since shifting between 1-4 is fine.   Am I correct?

 

Any advice and suggested are greatly appreciated.   
 

Thank you

 

SteveB

 

 

 

 

 

 

 

 

 

 

 

 

[JMortensen]

Had an issue with my ZX 5 speed twice, friend had the same with her Z or ZX 5 speed once, where the 5th/Rev shift rail would move out of position on its own. On mine, this caused the trans to go into 2nd and 5th simultaneously while on track (friend driving) and the rears locked and narrowly missed a brick corner worker's stand. The other two times was on the street. Friend's Z got locked into 2 gears also, think it was 1st and 5th that time. Last time was something like you described. This is 25 or so years ago, can't remember the specifics. The track one was fixed by fairly violently moving the shifter through all the gears. The other times the trans was dropped, the little access plug with the detent spring and balls was opened up and the rail moved with a screwdriver. I can't remember if it's the top or bottom plug for 5th/R.

The other thing that occurs to me is that I once had a bad clutch slave and it was leaking pressure. The car would shift into all forward gears, but not reverse because the trans never stopped moving and there is no synchro on R to help it in. 

Something that hasn't happened to me that I've read about is the shift fork roll pin shearing. When this happens you can move the shaft but the actual fork doesn't move, it just slides on the shaft. Racers used to swap out the later aluminum forks for the earlier steel ones and double pin the forks with solid pins, or use the hollow roll pins and run safety wire in them to double it up.

Yours sounds more like the first issue or the sheared roll pin. I'd pull it and pull the detent ball and see if the detent groove for neutral isn't lined up with the hole first, then open the case and check the fork of the detent is in the right spot. If you shift and see the shaft moving but it won't go into gear, then that tells you probably the fork isn't moving or is broken. Should be a fairly easy fix as compared to rebuilding the whole box.

[NewZed]

3 hours ago, SteveB said:

This car has been sitting for about 20 years.  

 

Do you know why it was parked 20 years ago?

 

I think that it's fairly common for people to get angry when they can't get in to reverse, because of a bad clutch cylinder, and to force the shift lever.  Damage to the fork seems possible.  You can get to the reverse/5th fork without removing the front case.

 

[SteveB]

Thanx

 

Not sure why it sat for 20 years.   Was told it ran when parked but nothing else.   I know it had quite a few issues once I started on it.  
 

First was that battery would have went dead quickly as the taillights were always on, easy fix with brake pedal switch.   It also ran poorly, even after new gas/oil/filters/full ignition tune up, coolant flush, etc. So I replaced all three of the sensors in the thermostat housing and now it runs great.   Oh, and I did put in a new fuel pump, as old one was crusty and full of crud.   
 

Clutch was also stuck when I got it but a quick tow in 2nd gear and then one pop of the clutch and it came free.   
 

Car does look like it has a newer clutch slave cylinder so clutch engagement might have been a problem before and they forced it into reverse, braking a fork.   Then replaced the slave cylinder thinking it would solve the reverse issue.   But damage was already done.

 

So I think your right.  Broken fork might be it.   I’ve do tons of auto repair but never taken a transmission apart.   If it is just a fork, is that something a novice can do?   I’m up for it if it can be done without a bunch of special tools or expertise.
 

Thanx

 

SteveB

 

 

 

 

[SteveB]

One more thing!   It will not go in reverse, even when engine is not running.   So I don’t think it will not go in because trans is moving.   I think it is most likely a sheared pin or broken fork as you guys suggested.   Guess only way to tell is pull it out.   It probably needs a new clutch anyway.   I’ll look for U tune video to guide me.   
 

Thanx again

 

SteveB