Transmission/Clutch grinding...

[Arrow]

Hey guys, I have recently noticed a strange and annoying noise coming from my transmission/clutch. Granted I also realize that my clutch is starting to slip some when I shift hard and fast, and also that there is a little bit of air in my lines that I need to properly bleed out.... But on to the noise:

Circumstances for the noise: downshifting from any gear into a lower gear without revving (rev matching) the engine. Also the noise happens once I enter the lower gear (not during neutral at all). If I rev match it while it's making the noise it seems to disappear (until it's no longer rev matched that is)...

Discription of the noise: a moderately loud grinding noise sounding like possibly a bad bearing or something catching (doesn't quite sound like the gears are grinding).

Any ideas what the deal is? The current clutch, pressure plate, and throwout / pilot bearings have 50k miles on them also the transmission was rebuilt (new bearings and syncros) about 40k miles ago... I also might have to change my transmission oil since it hasn't been changed in 30k miles (but I don't think that has to do with the noise)...

Any and all help would be greatly appreciated! Also, if you know of a thread that talks about something similar, please direct me there as I had no luck in searching (found some things and read them but the problems weren't too close to mine)

[nissanman04]

well just make sure you rev match right every time, lol.

but seriously i'm not sure what your problem could be, sry

[dickie]

could be your synchros going out? have you changed the fluid recently?

[Arrow]

well, like I mentioned, the transmission fluid (gear oil) hasn't been changed in about 30k miles - maybe a little more... and when I had my transmission rebuilt I had the syncro's replaced (not to say that they couldn't be the problem though)

My first reaction is to say throwout bearing, but I'm not sure and I really don't want to drop down my transmission unless I have to... but then again, I did help out a friend replace his clutch and associated parts in his Z28 - that transmission is monsterous (t56) - so I think that mine would be a lot more managable.