evolmotorsprt

I recently purchased a new to me 2002 C5 MN6 Coupe with 43k miles. I'm having a few issues that I'm trying to figure out before I take the car in to a reputable shop. The car has the stock original clutch.

I have an extremely hard clutch pedal that seems to get worse as I drive the car. I drove the car ~800 miles home. On the highway the clutch would get extremely stiff, and I had a few times when the car ground from 6th into 4th to pass. The clutch does, however, grab perfectly fine. It doesn't slip at all, even under hard acceleration. I've tried the Ranger clutch fluid replacement 4+ times and it hasn't really helped.

The second thing I have noticed is a airy/whirring sound that comes from the ashtray area. It sometimes becomes a faint whine at high RPMS. I'm wondering if this could be the front bearing on the torque tube. The sound goes away when the clutch is pressed. I can hear this when revving the engine and driving. There is sometimes rattling as well. It feels as if there is a resistance in the drivetrain fighting the motor.

I also have a vibration in neutral around ~1800RPM.

My brother basically has the same car, except his is a 2001 with 78k miles. I've driven both cars back to back. His car has a much lighter clutch and feels much freer to rev and drive. His car is what sold me on the platform to begin with.

I've accepted that the drivetrain will probably need to be pulled to diagnose the problem. It would be interesting to know if anyone else has experienced these symptoms, so it can help me explain my problems to the tech. Luckily I have a good shop here in Salt Lake (JDP Motorsports)

I really love this car and plan on making everything right. Thanks!

lane_viper

Mine has the same whirring sound and I'm thinking its the pilot bearing on its way out. The hardness could mean it needs a new master or slave or both.

I get to do all this in a couple of months as mine needs a new clutch.

evolmotorsprt

So I vacuum bled the system and was able to get some very small bubbles out. I have also continued to flush the reservoir with new fluid a la Ranger. For about 20 min today it was pure bliss to drive. Light clutch engagement, great shifts, clutch grabbing perfectly...

Well I was driving it around this evening and it's back to being a leg press machine. I'm beginning to think there is a seal compromised somewhere that is letting air in the system. The odd thing is my clutch is harder rather than softer, so I'm still stumped.

evolmotorsprt

This is another bump if anyone can help.

I took the car to a shop and they basically said live with it. Am I expecting too much with regards to NVH? I'm ready to pull and replace everything. I just want a car free of drivetrain vibration with a reasonable clutch.

vettenuts

Do you know the original owner or was the car from a dealer? You may have an issue with the balance as well and without the original clutch assembly is may be harder to resolve. You stated that you know a good shop in your area, can they help with the balance issue? Can you feel the imbalance when you rev the motor in neutral?

I suspect a system leak or possibly a mechanical issue with the pressure plate. It might be time to go in and take it apart, however I would do some reading on what others have done to take care of the balance issue when the original parts weren't available. Here is a thread, read post #33. It is a trial and error process. Clutch Balancing Thread

I would read as much as you can on this issue before letting anyone work on the car, knowledge is your friend in this case. Good luck.

evolmotorsprt

I bought the car from the second owner. As far as he knew, the clutch was original and I have no reason to not trust him.

The car does have the vibration in neutral at 1700-1800RPM. It lessens when I put the clutch in.

Of the shops I've taken it to, the mechanics say just drive it as is. Problem is I know it could be so much better.

Thanks for the response and I'll check out the above thread.

marc a

Have you pulled the bottom half of the bell housing off to see if there is any dampness around the slave? If so you are going in unfortunately.

If Slave is dry given the mileage, and the fact that you remedied the problem temporarily, I would replace the master and hose to slave. You might save yourself a lot of time and expense if this is the problem.

Bill Curlee

Could be any number of issues. Vibration that lessons when clutch is depressed tells me that you could have a pilot bearing issue and or TT bearing / rubber coupler issue.

If it grinds when shifting, you are damaging the trans. Get it fixed.

Plan on new TT couplers, clutch, pressure plate, disk, pilot bearing slave, throw out brg, AND master cylinder. MAKE SURE that you have the flywheel matched marked to the crank and if you replace the flywheel, OFF SET MATCH BALANCE the ne flywheel to the old one.

Bill

vettenuts

Sorry, reread your original post not sure what I was thinking in my first response since this is the original clutch. I agree with Bill, do a search on the torque tube couplers and bearings and see if any of the symptoms match what you are experiencing. I dropped the whole driveline several years back on my 2002, it wasn't fun but it wasn't hard. If the shops are telling you to drive it like this, I think I would find another shop or do it myself.

evolmotorsprt

I need to take off the inspection plate. This may answer many of my questions. I have already replaced the master.

I was able to get ahold of an old family friend who is a GM master tech and he pretty much said exactly the same thing. He also recommended having a GM tech do it, but we'll see what happens.

I'm thinking the majority of the problems are in the torque tube and TOB.

Looks like I'm going to tear into it. Thanks guys for your help. Now I need to find the right shop or maybe a dealer. If you have any recommendations in Salt Lake let me know.

Bill Curlee

What is your current HP/TQ level and do you ever think you will exceed 400-420 RWHP?

You have to pick a new clutch. That all depends on your END USE and HP/Tq goals.

Some things that I HIGHLY recommend getting/doing other than the MANDITORY clutch parts while you have the drivetrain out:

INSTALL A NEW GM OEM PILOT BEARING!!!!!!!!!!!!!!!
Install a remote bleeder kit!
Replace the output shaft seals in the differential!
Install a new OEM Master cylinder.
Drain and refill the transmission with new Synthtic ATF. I recommend the AMSOIL Torque Drive ATF.
Drain and refill the differential with GL5 75/90.


IF,,,,,,,,,, You remove the TT replace the rubber couplers with a set of GM OEM RUBBER COUPLES!

DO NOT use the DORMAN replacement couplers!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

evolmotorsprt

I'm at altitude ~4000ft, and this car is more of a toy for my wife and I to share. Right now the car has a stock engine with a Vararam and a catback. If anything, the furthest I'd probably go are longtubes and a mild cam. I'm guessing up here that would be 360ish RWHP. I don't want the car to be too rowdy for my wife to enjoy.

I was reading about the LS7 clutch, but think it may be overkill for my purposes. If I'm incorrect or you can recommend something better let me know. I was planning on putting in the complete LS6 clutch kit, hydraulics, etc.

I'm 100% with you on this brother. There's no way I'd have this thing torn down and not replace everything with quality parts. I'd also do the rear main seal and rear engine cover. I plan on buying the RPM TT rebuild kit. Are the OEM couplers worth it over the standard ones RPM sells?

BTW, thanks for the recommendations on the fluids.

Thanks again!

marc a

In my opinion there is no reason not to go with the LUK 04-905 kit for $250. LUK makes clutches for GM so you are getting a product that your power train will not overwhelm and probably last as long as you have the car. You will have to use LS6 hydraulics but you were going to do that any way. Add ARP flywheel bolts and you are done.

I bought this kit for just over $200 a couple of month ago just waiting for next winter's projects.

Marc

evolmotorsprt

Sound advice. I still fail to see why if the GM and Luk clutches are the same, why the GM clutch is 2.5x the price. I guess it's because GM can charge more just because.

huesmann

Corvette Tax.

shayden69

Ps I meant to make a frowning face at the fact that it's an automatic

dork

If you're gonna have to get into the drivetrain, why not replace the gears with 4.10s instead of going the LT headers/cam route? I'm guessing the 4.10s would give you at least as much seat-of-the-pants "HP" with the additional torque, without ANY impact on the engine's reliability nor need for upgrading, and the labor's already included. An RPM gearbox will run ~$1800-2000.