I just finished replacing my clutch and it feels like it drives great so far. The only thing is that sometimes when shifting into a new gear (most often on the 1-2 shift but sometimes on others), it makes a deep humming/vibrating sound and I can feel it in the shifter slightly. It only lasts for a second. It seems like it goes away as soon I release the clutch pedal. If I keep the pedal down it seems like it last just a fraction of a second longer than it otherwise would. Again, it doesn't do it all the time, maybe 30-40% of the time on the 1-2 shift and less with the other gears. Any ideas?
Here are the videos I just took. You can hear it right away on the 1-2 shift but you'll probably have to watch a few times as it is not very loud.
Thanks for the thought. The trans was rebuilt 6,000 miles ago by a company that specializes in T56s so that would be a surprise!
I been observing it more and here are some additional things I've noticed that make me think not a syncro...
It will "hum" even after it is in the new gear until I re-engage the clutch. It made the humming noise again last night and I just kept the clutch pedal down to see what happened and it continued for about 4 seconds until I let the peddle up.
Pulled the trans this weekend and found the culprit - a slightly bent flange on the throwout bearing. I replaced the pilot bushing while I was in there too so it could have been a contributor, but since the throwout bearing flange was visibly bent I'm pretty sure that was it.
I doubt the throwout bearing or pilot bearing is going to make the difference your looking for. I personally don't think theres a problem at all. The noise you're probably hearing is the disc rattling on the input shaft as you change gear. Every time an upshift is made, the disc has to be drasticly slowed down to match the next gear and sometime it will make noise. If it makes you feel better, my car has always made the noise your hearing.