G-56 guys, CLUTCH UPGRADE!! No more DMF!

[JHardwick]

helicopter dan has chopped and butchered this thread to the point that it can't be followed anymore ... ... ... I guess if any tangible developments occur, Tim will fill us in

 

[67guzzler]

Ha ha ha!!! Normally I find myself agreeing with your posts, JGann. But this one is pretty dang funny. If you had an NV5600 and felt like bombing it and also felt like maybe you needed a stronger clutch, you could go to SBC and get you one. That is a nice option I think. Now there will be one for the G56. I seriously do not get this kind of comment. I don't see people ragging on the Edge beta testers or whatever.



So good on Tim to offer up the truck. WTF is the big deal? But since he is already lined up to do that we need somebody else to do all us G56 owners a big service and go out and pull a 40,000 sled. My truck is modified somewhat so it that would probably invalidate the test. That leaves me out.

Alex -- I 100% agree with you. For selfish purposes as a G56 owner I think it's great that Tim is donating his truck to science for the greater good of G56 owners everywhere.



I was making the point that we don't know the real world capabilities of the DMF / G56 combo. Putting first things first, it would be nice to know what they are before investing in upgrades. Is that not logical? With the NV5600, I'd imagine there are a bunch of folks who've bombed those trucks and found out where the line is drawn. With the G56 mated to the Series 600 via a DMF, nobody knows. Maybe the default combo is awesome and can take 750 hp and 1500 ft/lbs of torque. Who knows? I don't.

 

[South Bend Clutch]

Alex -- With the G56 mated to the Series 600 via a DMF, nobody knows. Maybe the default combo is awesome and can take 750 hp and 1500 ft/lbs of torque. Who knows? I don't.

I do!!!



Folks, the DMF is not new by all means. This has been used in Europe for many many years. The 1987 6. 9 and 7. 3 Ford trucks were introduced with the Valeo drive train to the US and for the most part, when failure did occur, it was due to a couple of reasons, overloading the truck, bad engine performance i. e. bad injectors, etc. Also, the original design carried an 11" clutch so Valeo made a replacement unit flywheel/clutch, to move it to an 11 7/8". In 1994 they came out with the PowerStroke and made a heavier duty flywheel that supported a 12 1/4" clutch. Again, I saw many of these trucks get lots of miles out of the flywheel and clutch unless there was engine problems or too heavy of work loads. In 1999, when Ford went to the 6 speed, they went to a solid flywheel and tried to build a heavy duty spring loaded disc. This failed miserably. The disc springs broke out in short periods of time, especially with them heavy haulers. In 2003 Ford made the 6. 0 diesel and went back to the dual mass flywheel for the F250s and 350s and offered a solid flywheel system for some of the 350s, 450s & 550s. From day 1 none of the clutch systems could handle horse power or torque inhancements. This is obvious, the manufacturer builds to clutch system to handle the stock power. Now Luk came along and designed a solid flywheel replacement package for the Ford industry. This happened in the late 1990s. The units worked fine but would exhibit some drivetrain noise due to the lake of the dampening dmf. Did the transmissions start failing? No they didn't. But the clutch systems would not hold more then 300 hp, that's where we came in. The clutch for the Ford that Luk designed is actually a replica of the system Dodge uses with the 5. 9 Cummins. The Chevy 6. 5 in the early 1990s supported the Valeo designed clutch and flywheel. Again, it was fine for stock applications but any engine problems, enhancements to the torque, or overloading caused premature failure. Luk became very powerful in the industry with their solid conversions and got the OEM for the 6. 5 Chevy. The solid flywheel and clutch packaged designed for the 6. 5 failed miserably. The spring loaded clutch disc fell apart in short time. We converted many trucks back to the dmf. Luk then, in the mid 2000s, got the OEM for the Ford 6. 0, the Chevy Duramax and remained the OEM for the Dodge Cummins. Now, here's the company famous for the solid flywheel conversion now desided to put dmf in all of it's trucks. Most of the Duramax dmf fail within 30-40,000 miles and they have been scrambling to revamp the dmf. The Ford 6. 0s, same thing, put any horse power to the truck and she's toast. Now the Dodge. Folks, this transmission was used in Europe with the mid-sized Mercedes Benz trucks in the mid '90s as a test unit. It could not stand up and was dropped. They decided to bring the transmission (G56) back to market in the smaller truck i. e. Dodge Turbo Cummins Diesels. I believe their thinking was, smaller truck, less stress. The OEM manufacturers could care less about engine enhancements. The system is built for the power offered by the truck. In my opinion, if you leave the truck stock, keep it tuned, don't overload it, the system should last a good long time for you. There are also many passenger cars today being built with the dmf, Corvettes, Porshes, VWs, even Hyundai Tiberons, and many more. Again, everything works fine when the vehicle remains stock, once the horse power and torque is amplified many of them start to fail.



Back to the main topic, (please Tim, don't take this wrong) but I am not counting on or asking Tim to be a person to report back to the TDR forums with the results from ourselves and Blumenthals. I, along with Blumenthals, will together report our findings. There will also be an up and coming article in the TDR magazine. Folks, it was not like I had a dozen people offering their trucks for this type of work for me to chose from, I have thrown many leads out to see if someone would step up to the plate. Tim was the only one. Therefore, if and when something is designed, of course, it will be free to him. However, I am not about to automatically slap a solid system in his truck and wait to see what happens. This is the reason for doing the work at Blumenthals. I will have the experts in the transmission field, along with myself, going through the transmission to see if it will support such actions. I want to stress very loudly here, STOP THE BICKERING. If you leave your truck alone, for the time being, the system WILL perform fine. Our goal is to find out how far it can be pushed and what can be done to improve, if needed. Think about it. None of the transmissions, automatic or manual, dealing with torque converter or clutch, has been able to handle torque enhancements to a degree. What makes anyone think this setup will? It won't. Possibly mild enhancements but nothing major. I am not only doing this for you, or for us, but also for the companies that build the power modifications.



I hope this helps, and again, I will personally report back mid September.



Peter

 

[hasselbach]

great info peter. quick question. What is the main reason for the dmf? is it to allow a less strong transmission, or to reduce vibration to the driver. just curious.



thanks!

 

[South Bend Clutch]

Prob a little of both but mainly torsional spikes and vibration.



Personally, I think if the earlier 5 speeds had a DMF there would have been less 5th gear nut problems.



peter

 

[Gary - K7GLD]

great info peter. quick question. What is the main reason for the dmf? is it to allow a less strong transmission, or to reduce vibration to the driver. just curious.



thanks!

To put that question more precisely, IF the transmission was STRONGER to begin with, and the clutch adequate at least to previous margins, would the DMF have even been needed?



Did Ford and GM provide the DMF in their trucks for added smoothness, or to protect weak drivetrains? Maybe both?



If I may presume to condense what Peter said above, the DMF setup MIGHT be a plus IF the owner stays at stock power levels and loads, and operates the truck with relative care - but PROBABLY will be a problem if operated outside those parameters.



What all the critics here are saying is that the G-56 is a marginal transmission, and the DMF is more basically a bandaid to save it. I suspect the DMF IS largely for that purpose, but anything that benefits the transmission will ALSO benefit the U-joints, differential and various other parts.



The problem is that that "protection" comes at a price, and that price - as far as many HERE is concerned - is relatively low margins for upgraded power or load handling capabilities.



And for background perspective, Big rigs have the same firing pulse issues we do - how many of them use the DMF flywheels to smooth things out?



It still comes down to the basic question as to whether the DC move to the G-56 was a plus, or minus for new owners, as compared to the previous NV-5600 in terms of strength and reliability.



Personally, I realize that any time power is added, the clutch is at risk, and had to upgrade mine because of that - but having to upgrade the DMF at the same time really adds to and multiplies the expense...



And NONE of the above comments or questions are in ANY way intended as abusive to Peter, Tim, or owners of 3rd generation trucks!



These are all valid questions and concerns, and bringing answers to light need NOT be a cause of anguish and anger to ANYONE!

 

[67guzzler]

Personally, I realize that any time power is added, the clutch is at risk, and had to upgrade mine because of that - but having to upgrade the DMF at the same time really adds to and multiplies the expense...



And NONE of the above comments or questions are in ANY way intended as abusive to Peter, Tim, or owners of 3rd generation trucks!



These are all valid questions and concerns, and bringing answers to light need NOT be a cause of anguish and anger to ANYONE!

As a concerned G56 Owner, I couldn't agree more.

 

[South Bend Clutch]

Hopefully with the up and coming exploratory actions taking place by Blumenthals and myself, many of these questions will be answered. Until then it will remain a wondering debate with unsubstantiated facts. We can debate only with past experience of similar situations. It seems like many of you are demanding answers now and listening to speculation. Let's see what the facts bring to the table and then go from there.



Just a thought.



Peter

 

[FATCAT]

As a future CTD customer ....

This G56 thing is quite unsetteling to potential "maunal transmission" CTD buyers.



Could there be a possibility to swap out the G56 for a, lets say, FSO 8406A with a Solo clutch? Would this work (fit)? Or is there too much computer stuff to mess with.



Tim is a brave sole to be on the "bleeding edge". Maybe, Peter, if his G56 just is not able to be upgraded ... could you and Blumenthals talk Tim into a FSO 8406 conversion? This might be VERY interesting to future buyers.

 

[hasselbach]

reminds me when I built a 99 Camaro SS up for drag racing. . The stock clutch was crap, so we improved it. Broke the driveshat first time out. Better driveshaft, then the stock axle snapped. Better axles, then broke the ring gear. After a new rear end installed, pulled the trailing mounts out of the frame... sold car. . Too much work.



My point being, I'm sure SBC will make a steller unit, but it will be interesting to see what happens long term to other parts behind it. .



This should be very interesting for all.

 

[67guzzler]

In spite of my pointed questions and strong comments, I too am hopeful that the transmission and driveline can hold up to a solid flywheel. I really am.



Peter -- Could the driveline slack / clunking I'm experiencing be caused OR exacerbated by the dual-mass flywheel? Is it possible that the DMF is involved at all?

 

[South Bend Clutch]

In spite of my pointed questions and strong comments, I too am hopeful that the transmission and driveline can hold up to a solid flywheel. I really am.



Peter -- Could the driveline slack / clunking I'm experiencing be caused OR exacerbated by the dual-mass flywheel? Is it possible that the DMF is involved at all?

Of corse it is possible. It has been noted in the past with other vihicles equiped with the DMF. Is it for sure your problem? couldn't tell ya. Have you driven others? Did they feel the same way? Could you have gotten a bad one from the onset?



One thing that is very important to all with the G56 trans... When shutting down the truck, push in on the clutch pedal and hold it down until the truck is shut down. This unloads the DMF and relieves it from the violent end spikes when engine is shutting off.



Peter

 

[67guzzler]

Of corse it is possible. It has been noted in the past with other vihicles equiped with the DMF. Is it for sure your problem? couldn't tell ya. Have you driven others? Did they feel the same way? Could you have gotten a bad one from the onset?



One thing that is very important to all with the G56 trans... When shutting down the truck, push in on the clutch pedal and hold it down until the truck is shut down. This unloads the DMF and relieves it from the violent end spikes when engine is shutting off.



Peter

Good Tip! There is a huge difference in the reverberations when shutting down with the clutch out vs. in. There is way less racket when the clutch is in. Your explanation makes total sense.



I suspected it was bad from the start but two service managers from two different dealers say the clunk / slack is "normal for my configuration. " As you can tell I'm not convinced.



Regarding driving another G56 to test -- that would be ideal -- Unfortunately there aren't any G56's at the local dealer & very few in the area. Up to now I haven't called around to the local dealers but I just might have to do that and see if I could go for a test drive in another G56.

 

[hasselbach]

Of corse it is possible. It has been noted in the past with other vihicles equiped with the DMF. Is it for sure your problem? couldn't tell ya. Have you driven others? Did they feel the same way? Could you have gotten a bad one from the onset?



One thing that is very important to all with the G56 trans... When shutting down the truck, push in on the clutch pedal and hold it down until the truck is shut down. This unloads the DMF and relieves it from the violent end spikes when engine is shutting off.



Peter

How does pushing in the clutch prevent that? The flywheel is tied to the crankshaft, so how would pushing in the clutch in unload the DMF? I'm not sure I follow the logic...

 

[formula]

Well, one thing that will accomplish is to de-couple the rotating mass of the clutch disc, input shaft, countershaft and other gears inside the trans. This will give the DMF less shock to have to absorb.



Sean

 

[hasselbach]

Well, one thing that will accomplish is to de-couple the rotating mass of the clutch disc, input shaft, countershaft and other gears inside the trans. This will give the DMF less shock to have to absorb.



Sean

The disc, input shaft and other parts are not creating the torsional vibration, therefore do not contribute to it. I would think you would want as much driveline load on it to absorb the pulsing from the engine and therefore would want to have the transmission engaged.

 

[formula]

I think you're looking at this situation from the wrong frame of reference.



Sean

 

[Gary - K7GLD]

How does pushing in the clutch prevent that? The flywheel is tied to the crankshaft, so how would pushing in the clutch in unload the DMF? I'm not sure I follow the logic...

I think he is referring to essentially disconnecting the G-56 from the DMF/engine by pushing in the clutch - the DMF, naturally, will still be exposed to engine shutdown spikes, but not be exposed to many of the related rotating mass on the transmission side of the drivetrain...

 

[hasselbach]

I think he is referring to essentially disconnecting the G-56 from the DMF/engine by pushing in the clutch - the DMF, naturally, will still be exposed to engine shutdown spikes, but not be exposed to many of the related rotating mass on the transmission side of the drivetrain...

Yeah, but wouldn't the linear drag on the transmission side assist smoothing out the non linear spikes from the engine? Almost like a flywheel effect?

 

[Gary - K7GLD]

Yeah, but wouldn't the linear drag on the transmission side assist smoothing out the non linear spikes from the engine? Almost like a flywheel effect?

Dunno - that's what the REAL experts get paid to analyze - me, I'm a backyard, shadetree mechanic...