Coldmale

Noise in the transmission when sitting with the engine running, in neutral gear and foot off the clutch, ie driving the box.

Foot on the clutch and the noise dissappears

I had the motor taken out, changed the clutch and fitted a new thrust bearing. Aalso installed pfadt transmission mounts and changed the fluid. The noise is now twice as loud.

Opinions?
Is it the clutch bearing, or is it the gear box? - or is it the torque tube?

John

Coldmale

bump TTT

No-one have any experience of this?

John

songman3

What sort of clutch did you fit?

I have an Exedy GTO4SD and also have the Pfadt engine and trans mounts, and there is a fair old clatter clatter at tickover which is par for the course with these components - so I understand.

Once underway it all quietens down -in all, the Pfadt mount are not as hardcore as I expected, but the twin plate clutch does make more noise that the standard effort.

NOSZ06

It may be the old clutch chatter syndrome.
Mine is infected as well.
Gotta love the noises or it will drive you insane

Coldmale

The clutch (which is new) is the RPS Billet twin carbon.

I fail to understand why a spinning clutch (as it would be sitting in neutral with my foot elsewhere) would make any noise whatsoever. In 4o years of driving, I have no experience of that.

Interesting comments though as I hadnt thought of that

John

songman3

Sounds to me like what you are hearing is the famous 'twin plate' rattle - these units seem to resonate at a particular frequency.

I am not entirely sure why this happens, but the 'chatter' is very noticeable and well recorded event with performance clutches.

Running a big cam, etc, seems to make it even more apparent.

It does not take much wandering off the straight and narrow to turn the Z06 into a hardcore beast - probably the best aftermarket clutch for most folks needs is Katech's ZR1 conversion.

RoHo

My first thought would have been the throw out bearing since the noise goes away when you apply pressure to the clutch, are you certain that it is new?

DSteck

Sounds pretty typical of a twin-disk clutch. Turn your idle up higher and it will become quieter.

Knowles's Z06

I am having the same problem..I have been told it is called driveline lash..basicly slop in the driveline..the cutches aggervate this so I am told..i put in a 6 puck monster clutch level 6 and had my tranny get a level V face lift from RPM did the install at the same time, and what I got back with all these so called upgrades was a bunch of Fing noise...still trying to get to the bottom of it..because it is way to loud to let go..but right now everyone is saying it is the other persons fault I was told by RPM if i put in a clutch with not as tight of springs it wiould go away...but I am no one has offered to pay for the labor yet

Coldmale

We are on the same page

What I intend to do (over the weekend), is to pull the gearbox out, support the free end of the torque tube and start the motor

If it is noisy, it is either the clutch or the bearing

If it is quiet, it is the box.

B4 I started on all this, the car had 12,000 miles and apart from some noise, was a wonderful car to drive. With the suberb radio on, I could chat away with the wife and did not even notice the gear noise.

Now, as you say, it is one step from HELL. Even with a straight through exhaust (which keeps all the neighbours awake), the tranmission noise is woeful.

Cheers to you all

John

songman3

Good luck to you! I am almost tempted to say don't strip it down until you have Katech's ZR1 clutch to hand so as you can swap over clutches - it's a big job to have to do twice!! - and I'm pretty sure the Katech clutch will suit you better, in any case.

Hopefully it is a fault in the clutch, but as I say mine is very noisy too at tick-over - the whole driveline rattles and resonates, front to rear - I have a carbon prop as well.

It is very easy to turn the standard Z06 into a hardcore beast - all you need to do is change the cam, headers,exhaust, fit a twinplate clutch with a light flywheel, set it up with a tune that's not quite right, and you're heading for two shocks

First is when you start it up and waken the folks in the next town in the process - with cam, headers, and aftermarket exhaust you inescapably make much more noise than the standard car - mine does 88Dba at tick-over!
Next when you take it out into traffic and checkout the combination of a twin-plate clutch, lightweight flywheel, and a cam tune that's not right - you get a free training course that will stand you in good stead to win any Rodeo you care to enter - buckaroo.

To get the best from the car it is absolutely essential to get the tune correctly regulated - other than that you will be miserable with the setup you have anywhere other than the racetrack.

FI is the best way to go if you want more performance from a Z06 and want to retain stock like tractability/emissions/noise.

GM themselves offer a tuned version of the Z06 platform - the ZR1

Coldmale

Well thats almost exactly what I did. I have the ketech Torquer and its not a problem. Everything else is.

I am not going to change the clutch (too much money) and it works perfectly. I dumped the GT4 muffler and re-instelled the stock one, but the exhaust noise only dropped by about 30%, so its still loaud, but not loud enough to drown the transmission

I'll report back my findings once I remove the gearbox from the equation

John

Katech_Zach

The noise is the gearbox, amplified by the new clutch. I'm going to guess the clutch you put in is a twin disk or a single disk with stiff hub springs. There is nothing you can do about the gearbox itself. The root of the noise was there all along but now that you have changed the clutch you have amplified it. You can try tuning the engine speed in 25rpm increments to try to reduce the neutral noise, or you can change the clutch. You'll probably be very happy with the LS9X clutch. It is the only twin disk I've seen that has absolutely no neutral noise. GM needed a twin disk to hold the power of the LS9, but no way would customers buying a $125k car put up with neutral noise. So SACHS designed a twin disk for GM and man did they do a good job. It is a fantastic clutch that can hold a ton of torque and doesn't make any noise. Engagement is easy and pedal pressure is light. It has all of the advantages of a twin disk clutch and none of the trade offs.

Coldmale

Jason
I would suspect you are correct. The new $2,400 clutch is the RPS Billet Twin disk

I did look at the LS9 clutch at the time and I cannot remember why I made the decision I did. I had no concept of potential noise, so I did not ask that question of anyone.
I live and I learn I suppose.
Until the clutch fails, I will leave it alone and at the end of my track season (May - its just started), I will come back to you for the LS9 (and probably put in a ZR1 box at the same time).

In the mentime I will attempt to quiet down the box with an overhaul.

Thanks

John