Nick996

I had a local shop install a new McLeod RXT about 3 weeks ago. I was told about the break in procedure and followed it to the tee! I drove the car to work everyday and put the proper miles on it. It drives great, loved the clutch and thought everything was good UNTIL I drove the car hard.

I will attempt to explain my issues and hope that someone (anyone) with some insight might be able to help.

With the HP/TQ my car is putting out (LPE 660) I actually expected the rear tires to either "bark" with hard shifts and/or spin the tires. Especially with the RPM 3.90 gear diff I have.

Instead, it has a soft engagement that mimics a slipping clutch. The RPMs don't actually increase like a slipping clutch but the clutch is certainly NOT grabbing quickly/swiftly like it should. This happens with QUICK shifts only at the higher RPM's. If you're just driving around and not trying to shift quick, the clutch operates fine and you'd never know anything was wrong.

I've read that the OEM master cylinder in some instances isn't capable of moving the required amount of hydraulic fluid fast enough to quickly engage/disengage the clutch. Is this what I'm experiencing?

The shop I use said they've never had to change a master cylinder and have never seen this before. McLeod clutches are all they use and that it was installed properly. I was told the clutch comes assembled and basically all they do is double check the assembly and install it.

The shop called McLeod and they are sending a new clutch to my shop BUT my concern is that this will happen again.

Unreal

Did you measure and shim the slave properly? The one reason I don't recommend RXTs anymore is it is very very common to need to shim the slave for them to get proper engagement/disengagement.

Any shop that has installed a lot of them measures them now because their QC just isn't there.

Nick996

I had it installed. Not DIY. No idea what they did or didn't do.

Unreal

Well hopefully they step up and fix it at no charge to you. I know local shop ran went through 3-4 MC clutches on one car alone before they got one that would work.

Nick996

They are replacing it on their dime. My concern is if the SECOND RXT has the same issues. Then what? Ugh.

Unreal

Then just like the local shop, it spends 5-6 weeks there as they replace clutches until they get one that works, or they can start measuring them and send them back as they get them.

I wouldn't let them put one in without measuring, as you could land up on the other end and have a melted slave 1-2k miles later. RXTs love to melt slaves if not at the exact right height.

Nick996

So that I can be informed, is there an install procedure that goes through all this that you or anyone else might have a link to?

I do remember the shop saying they have never had to measure or shim a RXT before.

Unreal

https://www.corvetteforum.com/forums...5-preload.html

http://ls1tech.com/forums/manual-tra...ave-shims.html

Searching google pops up tons of threads on shimming RXTs.

Tech

Do you get chatter sub 2k rpms when you launch slowly?

Nick996

50/50... all depends on how well I can smoothly launch it but yes, I get chatter.

Tech

Seems to me there isn't much I can do except rev it to about 2k RPMs to avoid it. I have 800ish miles on it.

Nick996

Mine is mostly quiet. I think my chatter is just because the cam in my car is so large and I don't always get the throttle and clutch position perfect when I take off at low speed so it tends to chatter a bit.

I probably have about 600 miles on mine at this point.

ConfusedGarage

Check your engine mounts. Most start to leak out fluid and fail to do their job, resulting in numerous things: wheel hop, chatter on engagements, etc.

I have always had a cam and RPS clutch, I installed hinsons engine/trans mounts 2 yrs ago and all that went away after the install.

Nick996

Thanks. I did search but was hoping for specific Z06/LS7 content that was within a year old but didn't find much. Most of the things I've found and read are 3-5 years old. I would think if McLeod had such issues with all of it's clutch assemblies that it would have been resolved by now.

Scooter275

What clutch do you run? I was considering the RST or putting another stock one in with tick performance master cylinder. Car is stock but may get cam in the future.

Unreal

I currently run a mantic 9000. Had a few different ones in there. Mantic has been the only trouble free clutch of them all.

Millenium Z06

Mine has no issues, based upon your description, I'd say its not engaging correctly or more specifically that its an install issue, not a clutch issue.
I suspect that you may be right in that it will happen again but my guess is that it will because of the shops install attempt rather than the clutch itself.

rio95

My buddy and I both installed one recently and they work awesome and needed no shimming.

kyZ06

I just had a rxt installed at hpp on my built Z06 and its slipping horribly!!!! There driving my car to try and break it in more but im worried its shot!!!!

rio95

Uhhh if it's slipping breaking it in sure isn't going to do anything. Hate to tell you but you definitely have a problem. Most likely the slave is preloading the clutch.