So I've got a 1994 FD. Car currently has 5th gear synchro grinding issues but typically the gear can go/grind in and drive. Last night driving home it didnt' wan't to go into 5th. It felt rubbery like there wasn't a notch for the shifter to settle into. I gave the throttle a little blip and it managed to ease it into gear and didn't think anything at the time.

I drove it to work this morning and it seemed to be fine. However I took it out during lunch and it had the same issue. This time I could not get it back into 5th by revving the engine. While parked I got it into 5th by bouncing around the gearbox and shifting to 1st then to 5th (after a couple attempts anyways). As soon as I hit the highway I wasn't able to get it in again. Tried parking the car and shift from 1-5 again and after a couple attempts it went it.

Any ideas? Reverse works perfectly fine along with all other gears.

 

A piece of the synchro most likely broke off and got lodged in the shift gate. Time to rebuild the trans.

 

+1. the synchro's initially just crack, but i've seen them in multiple pieces, and it does not take much for a piece to jam something in there. if you're lucky the piece will come out, if you're unlucky it broke a hub or something

 

Additional diagnosis on the drive home today. It seems that 5th won't go in while the car is moving forward. At a stand still it'll go in about 20% of the time. It'll also grind into 5th if the car is slowly reversing.

I guess it may just go into storage early this year...

 

5th gear synchro isn't too hard to fix, you can just replace the synchro and hope there isn't more damage done.

Or, get a JDM trans for $350-400 and swap it in.

Dale

 

I'll probably end up just swapping in a used USDM or JDM trans depending on what I can find locally. There is grinding into 2nd and 3rd at high rpms as well so it may not pay to try and repair.

As of this morning it might have corrected itself. I managed to get it into 5th while driving and now it can shift in and out again (still grinds of course).

 

I'm also a little reluctant to do any more work on this car this year. Before even hitting 200 miles of ownership with this car I have had to:

Fix exhaust leak
Replace struts/springs
Fix Brakes
Troubleshoot Boost System
Replace the twins (twice - forgot to tighten water lines so I had to redo. Actually I forgot the heat shield the last time so this will need to be redone again)
Troubleshoot Boost System
Replaced all boost couplers
Redo Vacuum Lines
Troubleshoot Boost System
Test and replace solenoids
Troubleshoot Boost System
Rewire broken harness clips
Clean and reinstall Fuel Injectors
New plugs
Troubleshoot Boost System
Redo Grounds
Install water temp gauge

You could say I've had quite the "welcome to FD ownership" package.

 

Welcome to the financial disaster.

Your not that far from Chicago where I saw this trans pop up for sale recently on craigslist.

93 Mazda Rx7 Trans 5 speed