Grab some coffee and catch your breath. This goes on for a while.

Found out an interesting little fact about my truck. The master cylinder for the clutch has a check valve. So? Who cares? The engineer put it there for a reason. Well, with the dual mass flywheel, the clutch assembly can move around enough to cause it to lock up against the throwout bearing. Then you can't push in the clutch. If you use your truck like a truck and pull some weight, that causes the clutch assembly to move more. More power, more movement. Simple. Then I fed my truck some Smarties and it locked up. I've had it happen a few times before but not recently. And when it did happen, it would resolve itself pretty quickly. Now it locked up tight and wouldn't work untill the truck sat for a couple of minutes after driving it for about 10 miles. Once the throwout bearing started pressing on the clutch, things got hot.

Why does anyone else care? If you have a stock clutch and do any work with it, I would recommend replacing the whole hydraulic works. The shop wants $400 just to pull and replace the tranny. An OEM clutch is $3-500. Flywheel is another $3-700. So if you have a problem and go cheap, you're gonna pay $3-$600 depending on parts. That's if you pull the tranny yourself and go OEM. I looked everywhere and talked to LUK and Southbend. LUK does not have a clutch for the G56 that can handle any more torque than stock. That comes from their tech department. I looked at every other manufacturer that I could find. No one makes a clutch for the dual mass flywheel that can handle increased torque. And the dual mass flywheel can only be turned down .0004 to .0006 inches and they recommend grinding instead of turning them.

Now the props to Southbend. I called them and got straight up answers. Even got him to recommend other manufacturers. How about that for customer service. BUT. Here's the deal. If you turn up the power, no one has an upgrade that can handle it. You have to get a solid flywheel and then you get some options. But you have to piece together the parts. Southbend has plenty of options for power. And it's one stop shopping. All the pieces are designed to work together. I asked about the whole check valve thing and without missing a beat he said "yup, happens all the time."

I know you can get other hydraulics from anywhere. The tranny shop wanted $500. I read Dodge wants $250 for their check valve setup. Southbend gets $300 for theirs. No check valve, beefier pieces and steel braided lines with aluminum wrap from end to end. Nice. Very nice.

Some other posts talk about the clutch sticking to the flywheel. That might be, but the pressure plate should still pull away. I think that most of these are related to this pesky check valve. I'm sure some craftier guys could drill this valve or cut it out, but I'm not that crafty.

So there you go. Feel free to PM any questions and I'll relate my experiences to you.

 

I observed the same phenomenom on our '05 for almost a year (prior to installing the SB DD).

Even though the LUK clutch would slip under extreme abuse (4LO 4th hooks, 3rd gear launches off the tree on 37"s ), it held fine for most normal driving... but would "lock up" (pedal very stiff and pressure plate not releasing) at more than 3/4 throttle.

If left alone, while stopped or driving, would take anywhere from 20 seconds to 10 minutes to release - cool off - depending on how "hot" it got with the skinny pedal.
However, pumping the clutch pedal - as you would with spongy brakes - usually reduced recovery time from 2-10 seconds.

IMO, that particular issue was caused by the check valve's inability to maintain enough residual hydraulic pressure, but we'd already planned on a DD with hydro upgrade, so didn't bother with addressing the OEM parts' problem.

BTW, the LUK clutch looked much better than expected once it was on the floor, especially considering it's hard life.
Plenty of lining left, "normal" hot spots on the flywheel and the pressure plate's unusual concave contour still intact.
Bet it has another 100K on it with a good hydro assembly!

 

There is no "check valve".

 

we had three of our 06's have this problem the kit from south bend has a solid flywheel with a real pilot bearing in it a disc that will handle 1000 ft lb, pressure plate and all new hydraulics

 

Same thing happened to my 06, thought it was my pressure plate locking up. One call to Valair for the 500 hp complete set up w/ hydro kit. Not another burp of a problem.