Tech

Definitely a bummer to have to redo clutches. Been there, done that, didn't even get a tshirt.

Put the first 20 miles on my car. Everything is behaving like it should. Low pedal still but I anticipate that coming up. Pedal pressure seems lighter than the RXT and the RXT was already very light.

Pitufina

Exactly what I thought on how the pedal was releasing at the beginning and what I noticed coming from the RXT, but its starting to move halfway. I have like 400 miles on mine but like I said earlier, mostly highway. I'm going to give it some more after the 500 mark before I consider it fully broken in.

I just noticed you live in STL. I live right across the river 15 minutes away.

Tech

Well, the chatter is gone but the trans grinds in 2nd at high RPM and crunches a bit in 4th. New GM master. New GM LS9 slave. New Monster LT1-S triple. Used RPM Level 7 trans (SinisterC6). The only part I reused was my MGW shifter. I'm using Wilwood EXP 600 fluid and have bled it twice.

0SNL/MonsterClutchCo

Unfortunately the clutch isn't going to select gears to give you issues, if you're experiencing issues with just two certain gears then there is internal damage more than likely.

If there was a clutch issue the grinding/problems would exist in every gear.

Turbo-Geist

What does it do with the back wheels off the ground when you try to put the car in gear? Do they continue to turn once you get it into 1st or reverse or do they stop?

With the clutch pedal depressed, does the car want to creep forward with it in 1st gear when revving the engine at high rpms or does it stay stationary?

Unreal

When I had a clutch hanging up, it would grind 2nd but be fine everywhere else. New clutch and shifted perfect, so I don't necessarily agree with it has to be tranny damage.

Tech

I'll test these things this evening. When the car was on the lift, I noticed putting the car in gear and reving it with the clutch depressed caused the axles to spin.

I also measured the slave for shims. There was about .480" of difference between A and B. I contacted Monster to ask them if that sounded right, because it would require a lot of shimming. They said to ship it.. that the measurements for this clutch "are odd". This clutch uses an LS9 slave.

Thanks for the suggestions.

Turbo-Geist

My last RXT 1200 was doing the same thing. It would grind 2nd during high rpm shifts and take forever to hit the other gears. Upon inspection, I found the discs were dragging badly even though the slave had full travel. I'm not sure if you could even get a 0.004" feeler gauge in there. I would try to turn the back wheels by hand with the trans in 1st and someone holding the clutch to the floor. It took a lot of effort and you could hear the discs rubbing against the flywheel and pressure plate.


They said to ship it back or just run it? The shims just put the slave in the proper position to allow for clutch and wear and give the fingers room to extend outward as needed. If the car is wanting to move forward when in gear with the clutch depressed, it sound like something is off on the clearance between the discs. It could be something dimensionally or not enough stroke on the slave. You said you installed a new slave. I'm not familiar with the travel on an LS9 slave. I know the LS1/2/6 travel 0.440" to 0.445".

Here is what you would want to check for after the clutch has been installed. I know, it's impossible to do on a C6 with the solid bell housing. I've been thinking about coming up with a solution to check this without installing the torque tube.

0.025" shims between the two discs to prove clearance.


A video showing everything freely spinning:

Tech

Sorry for being vague with "ship it". They told me the clearance was fine and to run it as-is.

I'm going to take the car to flat spot during lunch and see if the car moves when the clutch is depressed, trans is in 1st, and I slowly rev to 5500-6k.

Turbo-Geist

Good idea. Let us know how it goes. I posted another check above. With the back on jackstands and the car in neutral, the wheels will spin very easily by hand. You then have a helper put the trans in 1st and depress the clutch pedal. You should still be able to turn the back wheels by hand. There will be a little more resistance because you are now turning some of the parts in the trans but it shouldn't require extreme effort.

Tech

I just tested the car on a flat surface, car in 1st, clutch depressed and revved to 5500-6k. The car started moving forward close to 5k.

Unreal

That sucks.

Good news is the title of your thread is accurate.

Tech

Monster says the transmission must have internal damage if 2nd and 4th grind. I have an email into RPM to get their opinion. I'm getting a bad feeling about Monster/SNL Performance. They've blamed everything but their own clutch so far and even though it's dragging. Steve's logic was.. "The transmission is broken, so that has to come out. Since the trans is out, you might as well send the clutch to us to double check".

The way I see it is.. "The clutch is definitely broken, so that has to come out. I should consider having the transmission checked out since the car will be down while Monster looks at the clutch".

0SNL/MonsterClutchCo

We've gone over things with you and are helping you diagnose it. I didn't say send the clutch back to us, I said send us images and we'll go from there. It's very easy to tweak the disc during installation, and, given that the unit you purchased was tested prior to leaving there is a good chance something went wrong.

Nobody wants to hear that, I get it, but that isn't me/us playing a blame game. If the hydraulic system is thoroughly bled and you're having disengagement issues on a clutch that is tested prior to leaving here there are other issues - it's pretty straight forward.

As far as the transmission grinding. If it were in all gears I would say it's the clutch all day long, that said, a clutch isn't going to select gears to grind - it doesn't ignore 1st, 3rd, etc. and just grind in 4th and 2nd. Given the fact that you said you were having issues prior to this clutch install that's a pretty straight forward analysis.

And finally, since the transmission has to come out shoot me some images of the unit like I requested and we'll go from there, or, you can send it back to us for an evaluation if you want - that's your call.

Tech

Your words, verbatim were:

"When you get it out we can inspect the clutch then to see what the issue is on it dragging at 5000 rpm and can get it corrected."

When you said "we can inspect the clutch", it sure sounded like you wanted me to ship you the clutch for inspection. In a subsequent email, you mentioned pictures. I had some pictures when I installed it that I've already sent you. You didn't tell me which specific pictures you want, however.

0SNL/MonsterClutchCo

"We" means the guy installing it, which is you, and myself.

I replied to your email you just sent with those pictures. I'd prefer to respond to one venue at a time, either email or here on the forums. Email is quicker.

Here is the conversation you're referencing... not sure the samantics of posting it on a forum to argue for arguments sake -

Me - "The transmission is going to have to come out to get serviced as the clutch isn't going to cause it to grind in just two gears, there is internal damage.

When you get it out we can inspect the clutch then to see what the issue is on it dragging at 5000 rpm and can get it corrected."

You - "I'm very skeptical that it's a transmission issue since we _know_ there is a clutch issue _and_ other people on Corvette Forum said a dragging clutch also gave them high RPM 1-2 shift issues. I have an email into RPM to get their opinion."

Me - "If you have a 2nd and 4th gear issue there is internal damage on the used transmission you got, the clutch doesn't pick which gear works and which doesn't... I'm not interested in what people on forums say, I build clutches for a living.

Again, it's got to come out - once you get it out shoot me pics of the clutch installed on the engine and we'll go from there."

You - "I have pictures when I installed it. RPM will have no problem reaching the same conclusion then.

File_001.jpeg shows a mark that I made on it just to ensure I didn't mix anything up. There were marks in several places but I took this one because I couldn't easily see it."

Me - "They shouldn't.

I replied to your post on Corvette Forum as well.

I'm not being argumentative or attempting to be an *** and point fingers, it is my goal to make my customers happy and that's what I'm attempting to do here. I realize you're frustrated and this is written word, we'll get it figured out.

Think of it this way, why would the clutch take a 2-3 shift without any issues but not a 1-2 or a 3-4? Because the 2nd gear and 4th gear synchros are damaged... the clutch is a simple mechanical piece, it doesn't dictate what works and what doesn't.

Since I got that image, and it looks completely normal, when you get the unit out check to see if the main/splined disc is flat on the base versus the hub. Also check the intermediate disc as well.

There has to be something that is amiss since it left here perfect and now it doesn't operate like it should."


Again, not sure why you want to rehash emails we're sending on the forum, if you have a question about what my responses are I'd recommend bringing that up to me and not to a group on a forum that you did not purchase a clutch from and that do not work for me. As said, I'm here to make you happy - I'm not here to argue with you on a forum or debate this debacle with a large group as we all have better things to do.

When you get it out let me know.

Tech

I didn't post complete emails. I was just addressing claim that you didn't ask to see it. "We" could have meant SNL/Monster just as easily as it meant me/you.

Email or forum doesn't matter to me. But either way, I will be sharing my findings and resolutions here to help the rest of the forum. I'll be glad to send any correspondence with you directly via email like I have been from the beginning.

0SNL/MonsterClutchCo

I have nothing against you sharing information and the outcome/diagnostics on a forum, by all means.

If my emails/words get twisted or misinterpreted I'll respond on here to correct that - otherwise, we're good.

Tech

I have the trans out but I haven't thoroughly inspected the clutch yet. It's still in the bellhousing and bolted to the back of the engine. Tonight it will come out and pictures will be sent to Steve @ Monster and posted here if anybody wants to see them.

I'm stuck in the middle between Monster and SinisterC6 with about $6k wrapped up in a clutch/trans combo that is worse than my RXT and stock trans. I watched $100 of Joe Gibbs trans fluid go down the drain (figuratively, ofc) yesterday.

There is definitely something wrong with the clutch and I hope that isn't making it seem like there is also something wrong with the trans. Has anyone else had a dragging clutch only cause high RPM shifting issues in 2nd? I can't shift quite as fast into 3rd or 4th, nor do I have a safe place to do that anyway. So I'm not sure if it's _only_ 2nd, but I tried once in 3rd and it didn't grind.

I could put my RXT back in with SinisterC6's trans to test it. As if replacing clutches were fun or something. :

Tech

I don't suppose you know if a C5 bellhousing is dimensionally similar enough to bolt one on a C6 and perform the same test?
I guess I could see if I could find a busted C6 bellhousing if not.