Might have blown my transmission.
 

Beautiful day in Dallas today so I decided to take my turbo S out for a short ride to enjoy the thrill of acceleration. Everything ran fine and I experienced no problems. Came home for a quick sandwich for lunch before running some errands for the wife. When I started the car up and let out the clutch there was a terrible knocking noise with the gearbox in nurtural. It goes away when I push in the clutch, but always comes back when the clutch is released. The car drives fine in all gears and I only notice the noise in neutral. Jacked up the car and listened with a stethoscope. Sure enough, its coming from the tranny.

Anyone have any idea as to what might be the problem? Anyone have a similar experience? Tomorrow I'll drain the fluid and see if there is any metal.
I have only been running about 8 psi of boost and I'm guessing about 330 whp.

That's the bad news. The good news is that I bought an new 2004 tranny last week for $1450 and it should be here in about a week.

If the sound disappears when the clutch is disengaged (clutch pedal pushed in), it more likely a clutch problem than a transmission issue.

Since the 2004 tranny is on the way, I'd order up a nice strong disc and pressure plate plus the throwout and pilot shaft bearings and replace them when the new transmission goes in.

:iagree: .............Sounds like a problem with the throwout bearing to me.

I'd want to inspect the clutch as well. Your using a ATS unit aren't you?

Yeah sounds like it could be the throw out bearing to me.

If the S isn't your daily driver (I'd assume it's not) then I'd :burnrubr: until the 04 transmission gets in :D You can do some testing for the rest of us to see what breaks first lol.

Are you planning on replacing the clutch with the transmission as well?

I have only experienced a bad throw out bearing once before in a second gen RX-7. In that case the noise was more of a scraping, rubbing noise, and I could feel it in the clutch pedal.

Yes, this is an ATS clutch setup which uses an Nissan throw out bearing. It has less than 600 miles on it, so I feel its unlikely that its a clutch related problem, but anything is possible I suppose. In any case I'll have to drop the tranny and see what gives.

As far as the '04 transmission goes, what are the differences in the gear ratios? I was planning to save that for an ultra-light project.

I just drained the transmission fluid (Poyal Purple Synchromax) and it came out looking like new after about 2500 miles of use, so I'm now figuring throw out bearing. Oh well, while I'm doing this, I might as well install my Accusump, new axles, and cryo'd and REM'd differential parts. I'll post some pictures on those parts later today.

^ wow you got some nice parts going in there. What kind of axles did you get?

You can find the axles here: http://www.driveshaftshop.com/item152466.ctlg

From memory: 1st, 2nd, 3rd and 4th are shorter, 5th and 6th are longer.