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Issue going into gears

1 December 2023
1992 nsx.Hello everybody,I had a issue shifting into my 4th gear yesterday when driving.clutch in ,tried shifting into 4th but wouldn’t let me like there was resistance.I pulled over and forced the shifter into 4th gear (grinding heard maybe was a bad idea).it got stuck in 4th so I forced it back to neutral.I was able to shift into 4th gear again but it doesn’t feel the same/smooth(no grinding noticed).with car off clutch in shifting gears I notice 3rd/4th gear will sometimes not go into gear.i will put car shifter into 3/4 back to neutral then when back to 3/4 again sometimes had resistance.this is with clutch pedal pressed all the way in.checked the reservoir and still has fluid.Another thing to note is not sure how old the clutch is as previous owner didn’t state.Could it be linkage needs adjustment or maybe clutch issue?maybe master/slave is bad?let me know what you guys think and if you want me to clarify anything(trying my best to explain )
Just took off the center console look how rusty this thing is and all that grime 🤢


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The rust is a Red Herring. You can get all the parts to rebuild it, but probably won't make a difference for this issue. I painted that base when I performed the AT->MT conversion.

I recommend re initializing the clutch. Takes a few minutes.

I suspect the clutch discs aren't clearing the pressure plates.
There are various ways you can check for a dragging clutch; however, a dragging clutch usually affects shifting in all gears. The most obvious case of dragging clutch symptom usually shows up when shifting into reverse. If the shift into reverse is smooth / noiseless then I don't think you have a dragging clutch problem.

Page 13-5 of the 1991 service manual describes adjustment of the shift cables. You can check that adjustment to confirm whether it is correct and if not adjust them to specification. Page 13-4 shows the shift lubrication points. You can lubricate and inspect the bushings to make sure that nothing is broken. A loose / noisy shift lever could be a sign of a gear shift lever mechanism problem. As Drew notes, I think the surface rust on the shift lever bracket is a non issue.

My gut reaction is that you have a 4th gear synchronizer problem or a shift fork / change holder / select lever problem. It is a common shift fork for 3-4.

A dragging clutch is fairly easy to confirm and you can check the shift lever cable adjustment so do those first just to rule them out. If both of those are fine then I would plan for a transmission fluid drain (and maybe replacement). I suggest this not because replacing the fluid will fix the problem; but, because you want to check for metal particle contamination in what drains out and you want to be able to inspect the oil pump strainer for metal particles. If you have what appears to be metal contamination, take a picture, post and ask for advice on whether this is normal or fatal. If you actually find significant metal chips then you can probably fast track to this being a transmission out repair and I would not bother refilling the transmission. If you can't do the repair yourself then its probably time to put it on a trailer and find a competent shop to work on the transmission. If there is no significant metal contamination, you can try refilling the transmission with Honda MTF and see how it works. Fresh oil at the correct level might help with a synchronizer wear issue. Fresh oil will not fix a shifter fork problem.

Good luck.
@Old Guy is likely correct (as usual), his prognosis is dire though requiring a rebuild.

You might try double clutching for 4th gear. If it works, then more credence for a bad syncro. You can double clutch indefinitely or skip shift 4th.

If you can wait until the clutch requires replacement and then dismount transmission.

If you are able: I recommend dismounting the transmission yourself. This job is easy to butcher for a shop that isn't experienced. You can then send out the transmission to a known good builder and reinstall it yourself.

@Honcho has a very nice DIY on rebuilding a transmission as well. I've rebuilt my own transmission for the so called "snap ring failure" (really a casing failure) and it was quite doable as long as you are not rushed.
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