A drivetrain noise popped up this morning. I haven't done any hard driving in a few weeks, just the commute which is easy shifting and casual driving - just fast.

The noise popped up this am on the way in. I tried to diag on the drive home. It is rpm dependent, so despite the TT projecting noises all over like a mime, i know it is not the new transmission or rear end. Though I really wish the noise was present a few weeks ago when I did the trans swap because it would have been insanely easy to refresh the TT or replace the clutch. Dang, right?

So any time I rev above 2500 rpm with the clutch engaged I get a little table saw noise. I hear it more right now because I just changed shifters last night and the boot isn't sealed over yet so I get more direct drivetrain noise.

If I had to guess? A coupler going bad maybe? Clutch wearing low? It engages fine, has held power fine. I don't want to rev up to test this but end up nuking something.

If anyone is familiar with similar instance of noise, I am all ears. For now, I'll start grabbing fresh bearings and maybe nix the oe style couplers this time and go back for six shooters or similar. And if I have to go that deep for the TT on a car with welded headers to thr mid pipe (original owner did it, I undid it, then Ibalso re-did it... So I pay the price again) then I may as well do the clutch and the rear main seal while I'm there.

Didn't want to be this deep in the car again until next year, but it is what it is.

Are 10mm tt bearings the same part numbers as the 12mm? I know I have at least one new spare.

And who has spotted the best deal on a fresh ornlow miles RST or RXT?

 

Which shifter did you change to? I tried the early TMOD with a non-isolated shift shaft and it made significantly more noise than the original. So much so that I ended up going back.

And no, 10mm TTs use a different bearing set than 12mm TTs. One or two are the same, I forget which, but not all three.

 

Thanks. It isn't tub or shifter nvh. It is a direct metal to metal high speed rotating noise.

It remains rpm dependent. Though it does not always occur. And I believe it occurs more often when I shift vs while in gear. It is also more prone when in gear to make noise on neutral throttle vs under slight load.

Hoping it's not the newer transmission, since it is more common at shifts.

Fun and games.

 

Moved to C5 Tech.

 

More details.

It remains RPM dependent. However, it occurs when I downshift and the engine is expecting to go to that RPM - but it not yet there, clutch still depressed - and so I believe it is a function of the new used transmission.

I guess this weekend I will try to change the fluid and hope for the best. It was pretty black when I checked the level. Fingers crossed.

And if I have to yank the thing again? I think I may just try my hand at breaking it down myself and replacing what's busted since I am going to try for a week off coming up. We'll see. I'd need to invest in tools as well as guess at a few parts it may be after talking to a pro.

No luck! I did record a video of it last night. When I get to slow down for the night I may toss it on YT and link here.

 

Hey Tusc- I experienced that "buzz saw" sound you're referring to in my '99 almost 20 years ago. It was caused by failed couplers. And if memory serves some of the welded balance weights from the main shaft broke off. I swapped in an entire tube from a 2002 which is a slight upgrade to the earlier years '98-00.

It started out making the noise subtly. Then after a few rips against my buddies Z06 it was a constant racket. Just like a buzz saw..

 

Speed Inc
https://www.speedinc.com/
They are pretty competitive, on price. I just did the RST and...
MCC6912-07 McLeod RST twin disc clutch assembly requires flywheel 460530 $739.99
MCC460530 Mcleod LS Billet Steel Flywheel for use with RST/RXT $329.99
Little cheaper than Summit. They are a busy place and can be hard to reach, but they should call you back if they are busy out in the shop.
Edit: I'm not sure if they stock them, if not, you could ask if they can drop ship it from their supplier.

 

Thanks for the link!

I'm not certain now which needs attention.

Clutch in, free rev, no noise
Clutch out, neutral, free rev, noise

And it will occur when shifting down, clutch still in, to a gear where the engine rpm would be above threshhold.

So I am wagering some synchro or other in the trans is angry. Which sucks because I have been shifting gingerly and enjoying the 'new' trans. Driving fast, but not slamming gears, very clean shifts. Bummer. I want it to be a coupler or part of the TT, but I can't think of what might assign the noise to the situations above since it is just a simple rotating assembly without gears.

What else might fail? Is there a throwout style bearing at the back of the TT?

 

This is exactly what mine sounded/ acted like when my couplers went bad.

 

Yeah that sounds about right, but still in the quiet stages. I grabbed a 12mm TT this morning, along with a tunnel plate when I saw a few standing there. If you're in the northeast, NextGen Parts in Spencer, MA is the place to go. Josh and team strike me as good people.

I've also got a C&S rear plate coming. Fidanza sells a replacement friction ring for just $76. And I'm seeing brand new RST clutches for $720 right now. I'm not trying to add to my expenses on a car I still intend to sell, but taking the drivetrain down twice is going to be my limit on that car as I don't want to waste the time and energy on the one I want to move along. It's getting a tunnel plate again now also. That and the trans mount (pfadt) were two de-mods I had done on the car which I regretted. Also the coilovers. But the goal here is controlled expense and effort, not another side project/build.

 

The 12mm TT upgrade is a good call. If you were keeping the car even better. I've got a new C6 tunnel plate sitting in my home office. Forgot that I'd already put one in years ago. I may attempt a double stack if I ever get around to it. I get up to Massachusetts a few times a year but always along the coast. My wife is from Reading. I'll have try to fit in an excursion to Spencer to hit up Next Gen. Thanks for the tip!

That $720 on the RST is the cheapest they've been in a long while. How much did you find the RXT for? American muscle was the cheapest last I checked at about $1400.

Good luck with the repair and hopefully your day goes better than mine. Planned to mow the lawn to mulch the leaves then take the vette out before date night with the Mrs. Two hours later I was on my back in the yard changing a mower deck belt that broke. Half the lawn done. OCD is now getting the best of me with my half ***'d clean lawn! And too bad a mood to take the car out.

cheers!

 

Only light labor and maybe later on for the coupe today. Right now I'm researching which diag / prog clone is best for my S600 and trying to confirm correct parts and part numbers to service that old battle tank. Hoping to expand my options for roadworthy vehicles in the short term.

 

I know that drill my brother. I've got a very nicely kept and well maintained by me 2004 BMW 645 ci Convertible. About 4 years ago I fixed the few things that were wrong with it after buying a $150 BMW scanner clone. I estimate my wife and I have driven that car 20 times since then. Good driver getting zero use. But nice to have the option.