I own a 02 Chevy Silverado 2500 HD with the ZF-6 and have already had the flywheel replaced about 8 months ago because i got tired of waiting for a design that i thought was made up. Since then i added an edge with attitude monitor and now the clutch pedal stiffens and doesn't come back up at high levels of torque and acceleration. After i pull the pedal back up with my foot, everthing is dandy. At least until i lay into it again. To make problems worse, the flywheel is grinding again and i was curious if anyone else had this problem and whats the best advice to solving my problems.

turn down the EDGE, your clutch is slipping.

But why does the pedal stay on the floor until i pull it back up? It doesn't seem slip, because it will respond immediately, its just the problem of the stiffening and clutch pedal remaining at the floor. By the way, whats your advice on upgrading my trans, because the flywheel is going to have to be replaced anyway.

I have read that the reason the pedal gets stiff is because when the clutch slips it raises the temp of the hydraulic fluid in the clutch system.

My 02 six speed does the same thing. I just recently bought a predator programmer and on the 65 hp setting I can slip the clutch with ease when I get on it...and on the 40hp setting my clutch does the same as you describe in 5 and 6 gear only. I'm not surprised about all this though, I noticed a little clutch slip when it was stock, but I've got 60,000 hard miles and tow some big loads. Anyway, I just got done ordering a heavy duty clutch kit for mine, I figured It needs a new one anyway so I might as well put one in that'll last forever. Didn't really plan on spending the extra $$$ though..:o:


Hope this helps.
J-HEFF

J-HEFF

What kind of clutch did you buy? Did you order a flywheel also?

I guess the clutch took all of my foot it could stand, so im obviously going to have to upgrade some the trans components. I'd like to know what clutch kit you recently ordered for yours and what you think about the new flywheel chevy is supposed to have. They replaced mine once already, but with the original design and old problems have come back into the mix of things.

alot of people here use this one.
http://www.macs-performance.com/

Str8 Eight-

I did some searching around and found a bunch of oem clutches for cheap, but obviously I don't want to put the same one in. I finaly found one from www.drivetrain.com/heavydutyclutch.html (http://www.drivetrain.com/heavydutyclutch.html). The price is a little steep, and I wouldn't be surprised if there was one cheaper, but after talking to these guys they assured me I wouldn't have any problems EVER with it. It also comes with some warranty which makes me happy. Anyway, should be a good clutch kit, I will install it next weekend most likely. Hope this helps, good luck!

J-HEFF

J-HEFF

Are leaving the stock flywheel in? Thanks for the info.

Yeah, I just had my flywheel worked on about 5,000 miles or so ago, it was all warranty and was just the updated version. I asked the guys at drivetrain and they said everything should be fine, they just said when installing the clutch kit they recomend resurfacing the flywheel with a 220 grid stone. All in all I figure I should be fine since I will mostly likely never run my predator over the 65hp setting. I use my truck for towing too much to run the higher settings...maybe a run at a track or too though...hope this helps.

J-HEFF

Hydralic clutches use brake fluid. It is very possible that the fluid boiled, releaving the pressure. The same thing can happen to your brakes, esspecially if water gets in the system.

I just installed Edge Juice w/*** and also bully dog pup. Planning on installing air intake and 4" exhaust system. What modifications do I need to consider for my Allison trans?

Not quite sure, you might try posting in one of the performance threads, since we are a bunch of old school "stick" guys.:) I thought bully dog made some sort of kit for the allison though. I know you can buy a rebuilt alli that'll hold all your power, but they come at a price. I think it all depends on what you what to spend. Good luck in your search!!!
J-HEFF

J-Heff

When Chevrolet replaces the flywheel, they should have to replace the clutch too. If the flywheel is defective, then the clutch is going to have be worn unevan. My flywheel is acting up again, and i've considered just forgetting the dealership and buying the components myself. I hate to pay for something i could get free, but im tired of hassling with all the problems. What would you do in my situation?

The reason that the pedel stays down is because the clutch trys to adjust itself to stop slipping and it sticks. It dont work... If you are putting a aftermarket clutch disk on the stock flywheel you are asking for trouble!!!! THe disk will not slip as ez so it will tare the flywheel apart faster.. when you stand on it the flywheel maxes the springs in it out and can stick that way.. Worst case the flywheel can come apart after alot of abuse and come though the bellhousing ( just pray it goes down not up thugh the floor!!!) If you can GET RID OF THE DMF!!!! if not you are :sheephump . If you want a complet flywheel and clutch set up let me or Cpmac know

OSUduramax-

No offense, but your post was anything but comforting;) :)

I was told from the company I was ordering from that my flywheel is more than capable of handling this clutch, due to the fact I'm not pushing huge power through it. I'm not running a huge setting, just 65hp on the predator programmer, so won't the flywheel hold okay??? I'm sure your more knowledgeable than I am on the issue, so I appreciate your input.

Stormcloud-

I should be more specific when i talk about my flywheel, I had my flywheel housing replaced, it was vibrating and making noise, so it was worked on. I appologize for not being more specific. They also didn't replace my clutch. This was about 5,000 ago, now I have over 61,000 and just experienced the clutch problem. I don't blame you for not wanting to screw with a dealer, they can be a real hassle sometimes.

didnt mean to make you uncomfortable just wanted to inform you of the options and posibilities. yes it might work with 65 hp but i see stock trucks take out flywheels as well as juiced trucks. i took out my 2nd flywheel with a hot juice on 2 and a tandom duel trailer hauling my gas puller. you will prolly be fine! i think i speak for more than just me....DMF are a problem in the dmax just as much as the disk. It wears out also and will fail someday... sorry for the worry..

OSUduramax-

I have a guy that lives close to me, his bellhousing did go to peices. The flywheel already raddling and the 32 foot dual tandem gooseneck which im sure had more than ten tons on it at the time didn't help. I'm going to have to visit macs-performance.com when they get through upgrading the site. Thanks for the information, i just wasn't sure about how reliable the new flywheel was.


J-HEFF

I waited on the dealer to send me some good news about the new flywheel, until i got impatient. So, i let them install an old design back in it. But by the way it sounds, i wouldn't be any better off with the new design. If i put a solid flywheel and a clutch with more holding power, would that cause my rearend to go before any of the transmission components gave me sign something was wrong? Thanks for all the advice and helpful comments.

OSUduramax-

I guess I'll run the flywheel I got untill the damn thing wears out on me, then give ya a call):h . I really appreciate all the insight though, I wish GM would get this clutch/flywheel problem fixed for good. They won't even build a lly with a six speed will they??? I think it's rediculous. Up here, every ford or dodge pickup you see has a six speed, and evey chevy/gmc has an allison. Maybe that's why we gm six speed guys don't get much attention, haha.

Stormcloud-

As far as rearends go, I've been told from a lot of different people and a few mechanics in our area that the gm rearends are about bulletproof. Now whether this is a true statement or not i can't say for sure, but I know I've never heard of anyone having problems with them, and my buddies driving fords and dodges all say they wish their rear-diff was as big as mine):h Obviously you can't judge by looks, but those gm rearends sure look tough! I'm sure there's somebody on this site that can tell ya for sure, but I would imagine there is nothing to worry about. Keep me posted on your macsperformance searching, I'd be interested in hearing if you installed something from them.

Thanks guys!
J-HEFF

[QUOTE=J-HEFF] They won't even build a lly with a six speed will they???
Quite on the contrary, you can find an lly with the 6-speed http://www.dieselplace.com/forum/images/smilies/wink.gif I have a feeling that sooner or later, mine is going to need a flywheel-transplant too http://www.dieselplace.com/forum/images/smilies/mad.gif

I stand corrected!:)


Does it put out the same power as an automatic? I thought I read somewhere that you could only get a 300hp 520trq motor with the tranny...that's why I assumed it was an lb7. Anyway, I appreciate the clarification!

J-HEFF

I stand corrected!:)


Does it put out the same power as an automatic? I thought I read somewhere that you could only get a 300hp 520trq motor with the tranny...that's why I assumed it was an lb7. Anyway, I appreciate the clarification!

J-HEFF No, they 6-speed lly's are detuned to the standard 300/520 rating the lb7 motor is...However...a predator helps that out just a little bit http://www.dieselplace.com/forum/images/smilies/hihi.gif

Ahh, it all makes sense now! It's still bull**** that gm can't make a system that'll hold the LLY 310hp 605trq rattings. I guess that ally is just too popular, for obvious reason. But I sure like having a manual, I find it much better suited for towing, but that's just my personal preference. That ally sure is a good unit though. So I have a question now, which runs better, the 300hp LLY or the 300hp LB7???:) Hmmm...

J-HEFF

J-HEFF

A lot of the boys back home have trouble with the allison around 40,000 miles, i drove an 04 model with the automatic and to me it downshifted really hard under a load. The problems with the allison are minor compared to the manual trans. if the allison can hold the torque, it seems that chevrolet could at least fix the flywheel in the ZF-6. I'm glad i found this site, cause for a long time i thought myself and two or three others were the only ones who had the flywheel problems, i guess because there so few manuals around my part of the country. I'll let you know something about the Cpmac setup as soon as i find out something.

I have a CPMac single disc setup. After trashing two stock DMF's (one w/o a box), I decided to bite the bullet and put something in that will hopefully last instead of the DMF junk. It's tough to eat the $1600-1700 cost when you're still in the 100K flywheel warranty, but I would rather tear down my truck myself and install a flywheel and clutch that'll last than have someone else screw it up and end up with something that won't last anyway. And when I was removing the bolts which hold the tranny to the engine, the topmost bolt which is difficult to reach, was not even hand tight. Most likely this was from not ever being tightened from the first DMF replacement.

The single mass flywheel is a little noisy at idle, makes a little more racket at low-rpms's under load, the so-called NVH (noise, vibration, harshness) factors (the reason for the DMF in the first place), but it's worth it IMHO.

I was a little hesitant since I was worried about whether there might have been a good (i.e. real) reason to use a DMF from a tranny perspective. I sent an email off to ZF one day, and the next day I received a very technical response as to why using a SMF would cause no problems to the ZF-650 tranny. I have the email saved somewhere if anyone wants it, PM me.

Tim

i really don't think that you can put enough power through the ZF to ever have a rear end problem.


yes that is a challenge because i would want to be the first to see it!

:grd:

Luvthesmellofdiesel

Is the new smf any noisier that the stock dmf when you were having trouble with it?

Only at idle, but it's not that bad, you'll get used to it. If you want something that'll hold, it's your only choice...

Tim