Long story short, I was driving my c5 a week ago and the clutch went all of a sudden. Now it won't go into any gear while it's running, but does so when it's off. We took off the inspection cover and see that the clutch is moving, but for some reason it is not engaging. I have a Tick Master cylinder but there's no signs of it being broken. I tried bleeding and doing the ranger method but no fluid is circulating out of the reservoir.

Anyway, my buddy is convinced it's the slave cylinder or something physically broke off inside the bell housing (piece of clutch, etc.). So it seems like we have to do take it all apart.

It's a big job, my friend is a mechanic and capable. I would be helping him. I already got the new rear main seal plate (updated version) and the upgraded barbell for the engine. I haven't ordered my clutch yet because I am very undecided on which to go with. I originally was going to go with the LS7 clutch, but a few people told me, including a shop that I inquired about doing the job, that the LS7 clutch was not designed to work with the C5 hydraulics and that the self adjuster can give issues. I was recommended to get either a RAM 12" clutch, or go with a monster twin.

My car makes 405 wheel horsepower. Has a cam, intake, and exhaust. I have no aspirations of making more power. I am happy with the performance, just want reliability and drivability. Better street manners is more important.

It seems the monster twin would be very overkill, but if it drives nicer than the LS7 then I don't mind paying extra to get it. I just want the best that will be ultimate reliable. I never plan on selling my car.

Also quick question, but how many people do the rear main seal plate? mine isn't leaking but I was reading people say to do it, but the shop that quoted me 165 an hour told me that they don't change a rear main seal if it isn't leaking because they don't want to risk a leak with a new one. Which makes me think maybe If I do tackle this job myself I don't bother with the rear main seal plate or barbell, since both of those are technically fine on my car at the moment and possibly messing with them could cause a leak.

If that were the case then it would be new slave cylinder, new remote bleeder, new clutch, and inspect the torque tube. I have the parts for the rear main seal plate if I decide to do it, but if the job is a nightmare then maybe i'll skip it and just do the seal. The main question I have is what clutch to go with. Please help!

Edit: Oh i almost forgot to include that there is a loud squeak now coming from the clutch in the bell housing. Not sure if it was always there and I never noticed before. But it's noticeable now. I think my throw out bearing went.

 

Why would you do the "ranger method" if you bled the system? Did you actually bleed the system at the slave or with a remote bleeder?

 

Sorry I meant I tried bleeding using the ranger method but even though I pumped it 50+ times the clean fluid never circulated out of the res. I have headers and cannot access the bleeder. The clutch went all of a sudden, it was working perfectly then I pushed it in and as I released it it started clunking while in gear. I put car into neutral and then it wouldn't get back into gear. It really felt like something broke inside. There are no leaks anywhere.

 

Got it. So that's not bleeding. Just so everyone knows what you did and did not do.

 

Thanks for that. Do you have any opinion on the LS7 clutch or go with something else like Monster Twin Disc?

 

At your HP level the LS7 clutch would be a nice choice. Especially if you do not need room to grow. Don't over think it. It really depends on how you intend to use the car.

 

this has come up a few times. The LS7 clutch is great, but it is also heavy. To get back down to factory clutch assy weight, you have to run an aluminum flywheel Again, nothing wrong with that, but it is additional expense. Higher the mass of the clutch assy, the higher the Moment of Inertia. The higher your MOI, the more energy it takes for the flywheel to change speeds, which basically means it makes the engine less responsive.
In addition to the added weighte LS7 clutch is 12" where the standard clutch is 11". Diameter of the flywheel also has a huge impact on MOI, this is why people run smaller diameter multi-disc clutches instead of a larger diameter clutch.
For very similar cost (including flywheel), you can buy a Monster S-Series or McLeod single disc clutch that has more holding power and a lower MOI

TLDR, the LS7 clutch is solid, but it will make the engine less quick-to-rev than the factory clutch.

 

I have the ls7 clutch in my c5 at 430rwhp, 11k miles on it no issues

 

I have had both the original and LS7 clutch and I can’t tell any difference in engine response. Perhaps it’s an actual thing scientifically or in race environments, but not that I can tell in my daily car. I do rolling starts to protect the trans/dif, but bust the tires loose frequently 😀 and the clutch seems to hold up fine.

 

You would absolutely be able to tell the difference between a proper aftermarket clutch and lightweight aluminum flywheel compared to stock or LS7 clutch/flywheel. It’s night and day the difference in responsiveness. Downshifts and up shifts, all around a huge improvement in driving experience. Downsides? Sure, a lighter weight flywheel requires slightly longer clutch slip, or slightly higher RPM from a standstill, but that’s it. A small, marginal sacrifice in one aspect for huge gains across areas where it matters. I have a McLeod RXT, but with your power level and no expectations of boost, doubling your power, you’ll be more than covered with the RST. It’ll hold 800 RWHP.

 

That's not what he said. He said he could not tell the difference between the stock clutch and the LS7 cluch he installed.

 

My apologies, I misread what he said.

 

Warmed over LS6 with 402rwhp. Dead stock GM C6 LS3/LS7 flywheel and clutch assembly with a Tick hydraulic TOB setup. No issues and works fine. Would an aluminum flywheel make things less heavy and quicker, yes. Would an aluminum flywheel make things fast and better at the track, yes. But even in stop and go traffic the stock C6 LS3/LS7 setup is just fine and it can handle the power all day long.

 

I doubt you will have any complaints with an ls7 clutch. That said I love my twin disk and aluminum flywheel and will be going that route on any manual car in the future

 

Thanks guys. Oddly enough I messaged monster about their clutch and they actually recommended if I do go LS7 clutch to not use it with the Tick Master cylinder, but go back to OEM.

It seems like the OEM master + LS7 clutch may be what I need.

RPM's being a little slower isn't that much of a concern for me with how I drive my car. I think I'd like the road manners better with the steel flywheel vs the aluminum.

 

Back when I was trying to choose a clutch I called McCleod and told them I didn’t race, about 375whp,, but did some mini street rips. They actually told me to go with the LS7 over the more expensive McCleod!

That was about five years ago and their twin disc was about $500 more. No regrets…

Ps. Also went with the GM master and slave. I had the shop install a remote bleeder and I flush it every year. Because I can, lol.

 

You won't be disappointed. I've been driving on Luk LS7 clutch kit with steel flywheel for almost 6 years. To me the biggest downside of this setup is the bell housing needs to come off due to the larger size (as someone else noted).

Yes, DO NOT use the Tick MC with LS7 clutch. Here are some posts I made on this topic almost 6 years ago:

And the follow-up:

 

I just ordered a Monster Twin Disk... give me a few weeks and I will let you know how it feels. I went with the 20lb flywheel.

 

I just experienced the same issue. I went with the McLleod singles disc and I am very happy with it. I could tell the difference right away. I would recommend it highly

 

I'm not familiar with the twin-disc clutches available for C5s. Is the engagement abrupt?

I am familiar with twin-disc setups on a different marque and there were complaints that the clutches can be hard to modulate to produce a smooth start from rest.