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DMF issue on 06
- Thread starter DBentley
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I am a tech at the local dealer and have already replaced 3 so far myself. The first was in a late 05 (bone stock)that had about 100,000 miles on it before it started vibrating like crazy. The second and third were on 06 trucks with both having less than 10K on them. On one the clutch would not disengage at all (Had Edge juice on truck) and the other the clutch pedal was extremly hard to push in after running the truck hard w/ the TST turned up. The good thing is the DMF are pretty cheap. Dealer cost is less than $200. 
Sure says alot for the quality, huh??
Sure says alot for the quality, huh??
Hearing about duel mass flywheel failure on 06s.
Whats going wrong Isnt a flywheel a large solid chunk of steel with a ring gear on the outer edge? whats the difference between a regular flywheel and a dmf.
This sounds like big $$$$ to replace.
DMF has another set of springs in the flywheel almost like the pressure plate. Wonder why they fall apart.
Have a friend with a brand new 07 manual. Hard on and off the throttle creates a loud clunk in the drive train. Not a good sign.
Don't hold your breath - DC has a LOOOOoong history of just looking the other way as related to well known problem issues...
Auto trannies in the '90's
Poor brakes and suspension premature wear '90's and beyond
VP-44's in 24 valve engines
Need more?
I've ordered a C&C with the G56 and is a worry of mine, but feel it will turn out OK and not worried about D/C warranty issues. However that being said it is the first thing replaced when warranty is up and look forward to all my choices of clutches because there should be a big aftermarket for the G56.
These have been tried by other makes and have failed and dont understand why D/C chose the DMF system.
It just gives me a good excuse, as far as the wife 's concerned, to install a upgraded clutch system.
I saw a brand new Mega cab in 06 that had not been sold yet pull a sled fairly well and was impressed by the way it took off with the sled.
These have been tried by other makes and have failed and dont understand why D/C chose the DMF system.
It just gives me a good excuse, as far as the wife 's concerned, to install a upgraded clutch system. I saw a brand new Mega cab in 06 that had not been sold yet pull a sled fairly well and was impressed by the way it took off with the sled.
DMF Features
DBently,
The DMF has needed a public relations office ever since it hit the US pick up truck market. Mis-understood, incorrectly serviced (Ford 7. 3L) discontinued for service (by GM on the 6. 5L) not to mention $$$.
The DMF's contain a larger Torsion Damper (noise filter) in addition to the Torsion Damper in the clutch disc (exceptions: F450, Super Duty -> '97, and D-Max, these were solid hub discs) the main purpose is to create the best possible in-cab enviroment. We equip them with leather seats, bun warmers, GPS, DVD, dual climate controls and generally load the truck, ask for 600+ TQ, and want to carry on a cell phone conversation with out shouting, the DMF helps do the job, it keeps the noise down. The noise filter and the actual addition of the secondary's mass to the transmission input shaft result in a quiet transmission. The Ford DMF (by my count, 128 pieces in a 7. 3L DMF) also has an actual torque limiting internal clutch pack that is designed to slip under excessive torque, think of it as a mechanical fuse. The entire system is tuned for torque capacity, service life, driveability, and of course $$.
One big difference that we are starting to hear about is the G56 out of balance failure. Look at the attached pictures, the one with the bushing completely out is from a D-Max, the other one was given to us by a fellow TDR member, look at the gap between the primary's pilot, bushing, and secondary F/W. About 90 degrees of the bushing is gone, looks like a cresent. When the secondary starts to orbit instead of being concentric with the crank, it goes out of balance, don't forget, the entire clutch is mounted to the secondary, that's a lot of mass to have shift off center and go out of balance. If you put your G56 in neutral, clutch engaged, set parking brake and increase the RPM and it starts to shake, that is a indication that the DMF is going out of balance.
We bought a 2007 G56 and right now, it has a prototype F/W and standard clutch, not the self adjusting type used on the G56, by mid March, our ZVT will be in it, and then I get to take it to the Mid America Truck Show in Louisville, KY. Then hopefully I will get to take it to some TDR events. I also have approval to host a Saturday get together here at Perfection Clutch, details to be announced.
DBently,
The DMF has needed a public relations office ever since it hit the US pick up truck market. Mis-understood, incorrectly serviced (Ford 7. 3L) discontinued for service (by GM on the 6. 5L) not to mention $$$.
The DMF's contain a larger Torsion Damper (noise filter) in addition to the Torsion Damper in the clutch disc (exceptions: F450, Super Duty -> '97, and D-Max, these were solid hub discs) the main purpose is to create the best possible in-cab enviroment. We equip them with leather seats, bun warmers, GPS, DVD, dual climate controls and generally load the truck, ask for 600+ TQ, and want to carry on a cell phone conversation with out shouting, the DMF helps do the job, it keeps the noise down. The noise filter and the actual addition of the secondary's mass to the transmission input shaft result in a quiet transmission. The Ford DMF (by my count, 128 pieces in a 7. 3L DMF) also has an actual torque limiting internal clutch pack that is designed to slip under excessive torque, think of it as a mechanical fuse. The entire system is tuned for torque capacity, service life, driveability, and of course $$.
One big difference that we are starting to hear about is the G56 out of balance failure. Look at the attached pictures, the one with the bushing completely out is from a D-Max, the other one was given to us by a fellow TDR member, look at the gap between the primary's pilot, bushing, and secondary F/W. About 90 degrees of the bushing is gone, looks like a cresent. When the secondary starts to orbit instead of being concentric with the crank, it goes out of balance, don't forget, the entire clutch is mounted to the secondary, that's a lot of mass to have shift off center and go out of balance. If you put your G56 in neutral, clutch engaged, set parking brake and increase the RPM and it starts to shake, that is a indication that the DMF is going out of balance.
We bought a 2007 G56 and right now, it has a prototype F/W and standard clutch, not the self adjusting type used on the G56, by mid March, our ZVT will be in it, and then I get to take it to the Mid America Truck Show in Louisville, KY. Then hopefully I will get to take it to some TDR events. I also have approval to host a Saturday get together here at Perfection Clutch, details to be announced.
That all SOUNDS great - and was an honorable and lofty goal, unfortunately the engineering, by DC and other makers simply doesn't match the goal...
SO, next question is, IF the primary goal was quiet and smoothness inside the cab, does that mean those guys installing the SBC solid flywheel setups are now driving noisy shakers?
How about it you guys who converted to the solid flywheel - are you seeing significant degrading of interior silence?
switching to the southbend setup was the best thing i feel i have ever done for my truck. got rid of the long start issue, and i dont have to worry everyday if the dual mass flywheel is going to come apart while driving and leave me on the side of the road. i recommend this to everyone with a g56. you will not be dissapointed.
Measured Imbalance on G56 DMF
We measured the imbalance of a new G56 DMF and the used G56 DMF that is in my first picture on our Hines Balancer. The DMF's were piloted on the pilot bearing hole using expanding collett tooling. The new DMF was less than 150GCM and the used DMF was just under 900GCM. we don't know what the total imbalance would be, because you also have the entire clutch on the out of balance DMF secondary. The balance values for reference equate to 10gm of mass at 15cm (10 x 15 = 150). The real imbalance comes from the combination of secondary and the entire pressure plate "orbiting" around the centerline of the engine, instead of sharing a common centerline and maintaining the balance.
We have sold a bunch of DMF to solid FW conversions for the 7. 3L's.
We measured the imbalance of a new G56 DMF and the used G56 DMF that is in my first picture on our Hines Balancer. The DMF's were piloted on the pilot bearing hole using expanding collett tooling. The new DMF was less than 150GCM and the used DMF was just under 900GCM. we don't know what the total imbalance would be, because you also have the entire clutch on the out of balance DMF secondary. The balance values for reference equate to 10gm of mass at 15cm (10 x 15 = 150). The real imbalance comes from the combination of secondary and the entire pressure plate "orbiting" around the centerline of the engine, instead of sharing a common centerline and maintaining the balance.
We have sold a bunch of DMF to solid FW conversions for the 7. 3L's.
I would not trade the SMF that I used in my 6. 5 for anything. The solid feel is so much better than the DMF 6. 5 trucks I driven. The only thing I have to deal with is a little more gear rattle/noise.
I can easily see the DMF to SMF swap becoming very popular for the G56, just like it is for the 6. 5 and 7. 3.
Isn't it even becoming popular for the D-max and PS with the ZF-650? I haven't been to those forums in awhile since I joined here.
I can easily see the DMF to SMF swap becoming very popular for the G56, just like it is for the 6. 5 and 7. 3.
Isn't it even becoming popular for the D-max and PS with the ZF-650? I haven't been to those forums in awhile since I joined here.
As mentioned in some of our articles and earlier posts, a properly built DMF is not a bad thing if it is used within its torque and load specs. Now I said properly built! DC is not the designer for this particular DMF. The job of designing the clutch system was subcontracted out to Luk as you will see the insignia stamped in the flywheel on the pictures provided. From 94-2005. 5 DC made their own solid flywheels and Luk made the clutch to fit. Mentioned earlier, the Ford 7. 3 from 1987-1998 used a DMF. Ford subcontracted a company by the name of Valeo for this system. We are next to Elkhart Indiana which is the trailer capita of the world. We have personally seen many of these systems last well over 300,000 miles. The primary cause of failure was do to exceeding the GVW or poor running engines, (bad injectors or fuel pumps). That is until power increases came along. This was the grave for the DMF. The DMF is NOT and I repeat NOT just there to quite the ride in the cab. It is there to protect the transmission from the diesel spikes transmitted form the engine. If you think about the difference between the two trucks Ford 94-98 and Dodge 94-98. The ZF 5sp was not reporting transmission problems whereas the NV 4500 5sp??? Think about it, do you think there would have been a 5th gear problem if DMF was used to absorb the spikes and vibrations. Don't know, maybe maybe not.
Let's put this into retrospect. 5sp Fords with failing DMF's... 5sp Dodges with failing springs in the 12 1/4" discs, not all but some. Why? usually there is a reason behind parts breaking. We have replaced 1000's of DMF's in the Fords and if the initial problem was not fixed or driving mannerisms not changed, the clutch disc in the solid conversion disintegrated just like the DMF. Believe me, we have seen our fair share of parts breaking with 12"-13" whatever we put in there. Nothing is fail safe when put to the test. Something has to give when the wrong environment is introduced. Unfortunately for us it is the link that connects it all together. LOL
The real problem is the design of the DMF. As Gary from Perfection stated, they counted 128 pieces in the Valeo DMF. The Luk design has probably 25?? not sure... never took the time to count them. I personally believe they tried to simplify the DMF to the point of self destruction. I guess we simplified it a little more by going to a one piece. LOL. You would have thought they learned this with the catastrophic failures of the duplicate flywheel in the Duramax beginning 2000. It has been so bad with the Chevy diesels that they opted to drop the manual transmission in 2007. As a clutch company, this really CHAPS MY BUTT!!! We made a solid flywheel conversion for the Duramax that works like a dream and not a person in our shop has an engineering degree. I do believe we have a good understanding of clutches simply because we see the aftermath and are able to view the weak points then address and repair them. Funny thing is, we have been at this for 50 years and quite often see the same products/designs in the newer vehicles that failed miserably in years past. Take a look at this... http://www.southbendclutch.com/images/Dscf0062a.gif This is the disc for the 7. 3 6sp Ford 99-02. The disc they used to eliminate the DMF. The first one that walked in our door raised a brow. John Deer used a similar design with the long springs and failed miserably. You cannot spin a disc with long springs and not expect the spring to bow in the center. This puts an ungodly amount of pressure at either end of the spring where it is encapsulated, braking the retainer and causing the spring to fly out.
In the past we have prayed on the designers faults/flaws and was a big part of what built our company. Now we fear that it is becoming such a problem that it is jeopardizing the manual market. It would be nice if they drop their pride and sat down with a person like me while designing and maybe some of the premature failures could be nipped in the butt. However, you cannot expect the OEM do build the parts to handle 1300 ft lbs. of torque and keep the truck at a decent cost for the consumer. It is your choice to add the power and that is where the aftermarket comes in and what keeps America running. Simply to come off the assembly line without problems, problems that could have easily been resolved before production would be nice!!!
Yes, the DMF used in the DTC is going to be a problem. Yes, we released a solid conversion in the beginning of 2006 purt near when the trucks were released. It is a simple design that has worked in the past and appears to be doing the job for the ones that have changed over. Yes, I think the DMF is good for the truck and would love to sit down with deep pockets and build one. As for now, a properly dampened clutch disc will do the job and reduce most of the vibration and diesel spikes produced from the engine. Word to the wise, beware of clutch disc that are not a true diesel dampening design. Just because it has springs does not make it a diesel disc. Without names mentioned, some companies are offering products such as this without worry of the aftermath, just the sale today.
Peter
Let's put this into retrospect. 5sp Fords with failing DMF's... 5sp Dodges with failing springs in the 12 1/4" discs, not all but some. Why? usually there is a reason behind parts breaking. We have replaced 1000's of DMF's in the Fords and if the initial problem was not fixed or driving mannerisms not changed, the clutch disc in the solid conversion disintegrated just like the DMF. Believe me, we have seen our fair share of parts breaking with 12"-13" whatever we put in there. Nothing is fail safe when put to the test. Something has to give when the wrong environment is introduced. Unfortunately for us it is the link that connects it all together. LOL
The real problem is the design of the DMF. As Gary from Perfection stated, they counted 128 pieces in the Valeo DMF. The Luk design has probably 25?? not sure... never took the time to count them. I personally believe they tried to simplify the DMF to the point of self destruction. I guess we simplified it a little more by going to a one piece. LOL. You would have thought they learned this with the catastrophic failures of the duplicate flywheel in the Duramax beginning 2000. It has been so bad with the Chevy diesels that they opted to drop the manual transmission in 2007. As a clutch company, this really CHAPS MY BUTT!!! We made a solid flywheel conversion for the Duramax that works like a dream and not a person in our shop has an engineering degree. I do believe we have a good understanding of clutches simply because we see the aftermath and are able to view the weak points then address and repair them. Funny thing is, we have been at this for 50 years and quite often see the same products/designs in the newer vehicles that failed miserably in years past. Take a look at this... http://www.southbendclutch.com/images/Dscf0062a.gif This is the disc for the 7. 3 6sp Ford 99-02. The disc they used to eliminate the DMF. The first one that walked in our door raised a brow. John Deer used a similar design with the long springs and failed miserably. You cannot spin a disc with long springs and not expect the spring to bow in the center. This puts an ungodly amount of pressure at either end of the spring where it is encapsulated, braking the retainer and causing the spring to fly out.
In the past we have prayed on the designers faults/flaws and was a big part of what built our company. Now we fear that it is becoming such a problem that it is jeopardizing the manual market. It would be nice if they drop their pride and sat down with a person like me while designing and maybe some of the premature failures could be nipped in the butt. However, you cannot expect the OEM do build the parts to handle 1300 ft lbs. of torque and keep the truck at a decent cost for the consumer. It is your choice to add the power and that is where the aftermarket comes in and what keeps America running. Simply to come off the assembly line without problems, problems that could have easily been resolved before production would be nice!!!
Yes, the DMF used in the DTC is going to be a problem. Yes, we released a solid conversion in the beginning of 2006 purt near when the trucks were released. It is a simple design that has worked in the past and appears to be doing the job for the ones that have changed over. Yes, I think the DMF is good for the truck and would love to sit down with deep pockets and build one. As for now, a properly dampened clutch disc will do the job and reduce most of the vibration and diesel spikes produced from the engine. Word to the wise, beware of clutch disc that are not a true diesel dampening design. Just because it has springs does not make it a diesel disc. Without names mentioned, some companies are offering products such as this without worry of the aftermath, just the sale today.
Peter
Last edited:
DMF Continued.
Lots of good information and discussion. The DMF as used in the Ford 7. 3L through 1997 did have the torque limiting feature. It was in the torque limiting friction material and bellvelle spring clutch pack that was inside the DMF. Several years ago, Valeo published a "fact sheet" on DMF's and the torque spikes were acknowledged during start up and shut down. These torque spikes were attenuated by the internal friction clutch of the DMF and allowed for filtering out of the spikes by a brief slipping of the secondary relative to the primary.
Valeo further states "The benefits of incorporating the DMF technology is the elimination of excessive transmission gear rattle, making driving comfortable at any speed (even with lower viscosity fluids as A. T. F. ), reduced shift effort and increased fuel economy" Notice the quotes, don't ask about the fuel economy statement, I don't know about that one.
We disassembelled a D-Max DMF a couple of years ago and did not find a torque limiting clutch pack. The G56 DMF is basically the same design as the D-Max. It is my observation from these parts that neither of these DMF's have the torque limiting, spike blocking internal clutch feature of the 7. 3L. That was only on the Ford 7. 3L and briefly on the GM 6. 5L.
Lots of good information and discussion. The DMF as used in the Ford 7. 3L through 1997 did have the torque limiting feature. It was in the torque limiting friction material and bellvelle spring clutch pack that was inside the DMF. Several years ago, Valeo published a "fact sheet" on DMF's and the torque spikes were acknowledged during start up and shut down. These torque spikes were attenuated by the internal friction clutch of the DMF and allowed for filtering out of the spikes by a brief slipping of the secondary relative to the primary.
Valeo further states "The benefits of incorporating the DMF technology is the elimination of excessive transmission gear rattle, making driving comfortable at any speed (even with lower viscosity fluids as A. T. F. ), reduced shift effort and increased fuel economy" Notice the quotes, don't ask about the fuel economy statement, I don't know about that one.
We disassembelled a D-Max DMF a couple of years ago and did not find a torque limiting clutch pack. The G56 DMF is basically the same design as the D-Max. It is my observation from these parts that neither of these DMF's have the torque limiting, spike blocking internal clutch feature of the 7. 3L. That was only on the Ford 7. 3L and briefly on the GM 6. 5L.
WOW, lots of GREAT insight and info in those last posts!
And before too many rocks get tossed at the OEM designers of the affected DMF setups, remember that their designs were undoubtedly overseen and controlled by specs and parameters dictated by outfits like Ford, GM and DC - I have little doubt that LUK, for instance COULD easily design a long-life expectancy DMF, IF given a free hand in it's design.
But that hardly likely in a penny-pinching corporate world!
It also seems logical that a properly designed DMF must be built to operate within a relatively limited engine firing impulse environment to cope with spikes, as well as a specific range of power loads - DMF springs that properly dampen spikes and loads at one power and load level, would probably be damaged or ineffective at one that is significantly different.
All that said, what about a different approach to smoothing and dampening engine impulses and power spikes at the flywheel- like the viscous dampening on the crank vibration dampeners used successfully for so many years?
And before too many rocks get tossed at the OEM designers of the affected DMF setups, remember that their designs were undoubtedly overseen and controlled by specs and parameters dictated by outfits like Ford, GM and DC - I have little doubt that LUK, for instance COULD easily design a long-life expectancy DMF, IF given a free hand in it's design.
But that hardly likely in a penny-pinching corporate world!
It also seems logical that a properly designed DMF must be built to operate within a relatively limited engine firing impulse environment to cope with spikes, as well as a specific range of power loads - DMF springs that properly dampen spikes and loads at one power and load level, would probably be damaged or ineffective at one that is significantly different.
All that said, what about a different approach to smoothing and dampening engine impulses and power spikes at the flywheel- like the viscous dampening on the crank vibration dampeners used successfully for so many years?
Gee, sounds like the same case many have made for International in relation to Ferd and the Sick Point Oh. What a shock.
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Issue 128 – Digital Version
Digital Magazines
FREE!
TDR Test Drive - Digital Edition
Renew
Subscribe
Gift Subscriptions
Back Issues
Subscription Status
Address Change Form
Buyer's Guides
Ram Diagnostic Trouble Codes
The Perfect Collection
The Perfect Collection Vol. II
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Dodge/Cummins Historical Overview
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What Makes Us Tick?
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