R33 GTR Clutch/Trans issues

[anobahar]

Hello everyone, new to this forum. New owner of an R33 GTR, bought it around last week. Have since drove the car about 2000 miles.

Since I got it the transmission has felt a bit "crunchy". Chalked it up to slight synchro wear, no biggie it's a 26 yo car that I got for a good deal. Not really sure if the clutch is stock or not.

Then I noticed a slight scraping sound upon having the clutch pedal released. Almost has a tapping sound that goes with it. Goes away when I press the clutch in.

Then within the last 24 hours, the issue has got so bad that I actually can't get into reverse, and the rest of the gears extremely crunchy. Along with this, the noise no longer immediately goes away when pressing the clutch pedal in, it takes a few seconds now to go away. As soon as the noise is gone, gears are free and I can get into them all smoothly again. Seems like some sort of a bearing or something gone bad, not sure about the technicalities on that.

Finally, I have tried adjusting the clutch pedal already. The clutch bites pretty evenly throughout the pedal, and has absolutely no bite when all the way down. It starts to free up just at the very top, so there is a lot of pedal travel with it. Probably can't make it bite any higher, will start to slip during regular driving.

I will say there is about an inch of dead pedal in the clutch. Clutch reservoir is filled all the way up.

Really would appreciate any input before I pull the trans and start throwing unknown parts at it. Thanks guys.

[r32-25t]

The only thing you can try with out pulling the box is bleeding the hydraulic system for the clutch and make sure the pedal bracket isn’t broken (has happened a lot). After that you’re pulling the box out to inspect everything in there to find the issue

[anobahar]

I will try that I suppose, although it doesn't explain the noise. I have a feeling it's the input shaft bearing in the box causing this noise.

"Suppose you hear the noise when the vehicle is standing still, the trans is in Neutral and the clutch is fully engaged (clutch pedal fully released). Most likely, this is noisy input shaft bearings. It’s not likely to be a bad clutch release bearing because there’s no substantial load on that bearing at this time. An easy, additional test is to apply some light load to the release bearing by resting your foot on the clutch pedal. If doing this doesn’t change the noise at all, it’s additional proof that the noise is inside the trans (input shaft bearings) rather than outside it (clutch release bearing)."

While pulled I might as well do the synchros too. I've never rebuilt a manual transmission before but I've built more than a few engines, so i'm sure I'll be able to figure it out. Any good source of documentation on this procedure specific to an R33 GTR box?

I suppose the only issue with this diagnosis is I'm not sure if a bad input shaft bearing would cause the box to not want to go into gear.

Edited February 3, 2021 by anobahar

[r32-25t]

The fact you can’t get it into reverse points it likely being a clutch related issue and not an issue with the box it self. 

[anobahar]

1 hour ago, r32-25t said:

The fact you can’t get it into reverse points it likely being a clutch related issue and not an issue with the box it self. 

You make a good point. I guess I'll just open her up and see what I find. Thanks!