I was poking around on ZF's website for information about the S6-650 tranny and noticed something interesting: according to the technical data they (ZF) provide, the transmission max input torque rating is only 520 ft/lbs of torque (reference value depends on vehicle data and application conditions). This doesn't seem like a very big number when one adds a power box to the Duramax.


I found the information at:


http://www.zf-group.com/pdf/lightTruck/s6-650datasheet.pdf.


Seems like the stock torque rating of the Duramax (LB7) is right around 500 ft/lbs or so if I remember correctly. I thought this was interesting. Maybe this is why the LLY is de-tuned for the ZF/6 and not just for the ongoing flywheel/clutch issues...


Thanks,


Tim

Both LB7 and LLY with ZF are rated at 520 ft-lbs.


The interesting thing is that Ford has offerred 7.3 PSDs at 525 ft-lbs and 6.0 PSDs at 560 ft-lbs (570 for 2005) with the ZF S6-650.


Makes me go Hmmmmmmmm.http://www.dieselplace.com/forum/smileys/Confused.gif


To the best of my knowledge nobody (either brand) has made the S6-650 grenade by adding power . . . on the other hand some folks have broken the flywheel with stock power, and with a little extra power the failure is nearly as predictable as sunrise.

When the allison first came out it's rating was 520 or 540 but now the lly has 590 so what's the deal

The only ZF failure I have heard of was due to a bouncing truck with large, heavy sled attached to it -- and even then I believe it was only the input shaft. It appears that the ZF will hold 900-1000+ ft lbs all day long.


The stock flywheel on the other hand is a joke...


Get a hold of CPMac -- he can give you the rundown on ZF and flywheel failure modes.

I am ready to buy one of Craig's setups as soon as I can get hold of him.


Btw, I sent a question into ZF and received a very timely and very informative response with regards to why GM is using a DMF and if there would be any problem, as far as ZF is concerned, with using a solid flywheel on this tranny. The answer from ZF was that GM specified the DMF due to noise concerns and that the S6 650, as delivered to GM, is capable of having a solid flywheel with no modifications to the tranny required. This is good news.


Thanks,


Tim

Good news on the solid flywheel. I am also going with Macs single disc clutch if I can get a hold of him. He is a hard man to catch.

Good news on the solid flywheel. I am also going with Macs single disc clutch if I can get a hold of him. He is a hard man to catch.


did you ghe hold of him? I have tried a couple of times - no response.

I did a couple days ago. Nothing since then. he said he had a family illness. I might try to call tomorrow.

Does anyone have any solid data on CPMACs new solid flywheel and clutch? I need a new 'kit' and I am willing to pay but I want some confimation first of it's performance and reliability. Help!!

I don't know, but I have his kit in a box in the garage which I plan to install within the next couple of weeks. I have high hopes and I think it is the right solution to the problem, no more messing around with GM's weak-a$$ed DMF's. What makes anyone think rev 5 will be any better than their previous 5 versions? As for the dual-disc clutch, I don't think it's necessary unless you're planning on pulling a sled or drag racing from what I have been told. I just want something I can run a 150hp VA box (or Quad 135) w/ and not tear it up. I still don't think I am slipping the stock clutch, I think it's just the flywheel that's gone (again)...


Thanks,
Tim

Ok, thanks. My DMFW started rattlin' again this morn. I am goin to hav to do somethin soon . . .

I should have CPmac's setup in Friday. I was originally going with the single disc, but if I can catch him before he leaves I am going to spring for the dual disc. I probably won't pull a lot just once and a while and I think the dual disc will be awsome with my GN trailer. I wish I had more moneyhttp://www.dieselplace.com/forum/smileys/Ermm.gif. I think I am going to try to pull this Mon. If I get the clutch in.

I should have CPmac's setup in Friday. I was originally going with the single disc, but if I can catch him before he leaves I am going to spring for the dual disc. I probably won't pull a lot just once and a while and I think the dual disc will be awsome with my GN trailer. I wish I had more moneyhttp://www.dieselplace.com/forum/smileys/Ermm.gif. I think I am going to try to pull this Mon. If I get the clutch in.


Did you receive your kit from CPMac? How about posting some pics?

I am checking in on monday to see the progress on the new flywheel. I want to know exactly what is going to hold it together differently than the previous 4. mabey it is a solid onehttp://www.dieselplace.com/forum/smileys/Hug.gif if not I have an 83 6.2 in the driveway with 4 speed I wish I could take that flywheel and clutch set up. ( that was the real clutch set up with no hydraulics) Hard pedal all the time hahaha.

Hey Peter;


I would appreciate your post after you get your "checking" done. I am also very interested in the "new" design. A single mass FW would be great. I have never heard of a dual mass design that did not have failures . . .

Craig got held up last week, but Iam now shooting for Sunday for the install. I am going to try to borrow a digital camera and get pictures. I will let you know how it goes.

Thanks and good luck.


BTW, all you ZF6 guys should check this and post an opinion:


http://www.dieselplace.com/forum/forum_posts.asp?TID=12442&PN=1Edited by: Deadeye

I'm not sure which model of the ZF6 I have in my F350, but I do need to R&R it.. I'm taking it to a shop next week or the week after for a OD problem.. It pops out of OD when going down the road, or when going downhill.. It will happen if you let off the throttle and then get on it again too.. It isn't the pilot bearing.. Something internal..