Dual Mass Flywheel Failure can cause catastrophic failure.

[HHhuntitall]

Customer called and said his trucks started vibrating and the clutch started making a lot of noise. He brought it in, and of course, the DMF failed horribly, like you would expect. No power upgrades, truck is used pretty hard, but not pulling a trailer. The original clutch was replaced by Dodge at 92k miles, and this one almost made 75k miles. Unfortunately, either the Dodge installation or the short term vibration caused failure of the engine adapter, and it was cracked completely through, outside to inside. Rear main was seeping, and transmission input shaft bearing was worn excessively. Bolt was broken off, and appeared to have been that way for a while. Perhaps this was from Dodge's install on the last transmission? Anyone considering an aftermarket clutch instead of a Dodge OEM replacement, you might consider the following.

 

[n7gxz]

Talk to Peter at Southbend Clutch.

Kevin

 

[RVTRKN]

Anyone considering an aftermarket clutch instead of a Dodge OEM replacement, you might consider the following.

View attachment 85000View attachment 85001View attachment 85002

Whats your recommendation?

 

[EDankievitch]

South Bend has a few options. I would favor an organic friction material clutch for a stock power level truck. I had done the Con/Fe single disk kit on my 05 and found that it would become very grabby in the damp humid air we have here in the northeast.

 

[NIsaacs]

Classic case of poor install habits, that transmission was forced together with the mounting bolts. The broken bolt is no doubt cross threaded and broken with an air gun.



Nick

 

[GCroyle]

Classic case of poor install habits, that transmission was forced together with the mounting bolts. The broken bolt is no doubt cross threaded and broken with an air gun.



Nick

I think Nick has big part of the story. The broken bolt, looks like it has corroded and is not a fresh break. Other points to inspect, condition of the dowel sleeves and matching holes in trans case. Needs to be checked. What does the pilot bearing look like? Normal or torn up? Condition of the other trans bolts, heads chewed up from impact gun or normal? Any evidence of any wiggling or the trans? Does is show a shine between mating surfaces to adaptor? Customer report any ongoing engine balance issues? How much rotation and rock does the secondary have to the primary? NOTE: Some rocking and rotating is part of the game. Any controllable noises from the clutch area?



Good luck.



Gary

 

[HHhuntitall]

Broken bolt wasn't crossed, probably just overtightened or bent at some point. It will move fairly easily. Dowel alignment pins were not too terrible, but one was left in the transmission, and transmission housing showed some signs it wasn't aligned when it was started together... . New adapter plate had two new dowels, which appeared to extend beyond any damage in the transmission casing. When pressed together by hand, there was no give, and they didn't want to let go. Bolts weren't rounded, casing didn't show any signs of movement except right around the broken bolt, so it went back together this morning with a new South Bend, new rear main, new front input shaft bearing and seal, and a thoroughly cleaned and washed G56. Gears looked pretty good considering how bad the fluid looked. I'm not sure it's been changed, even by Dodge. I took pictures of it, too, in case of failure. There were some extensive shavings on the drain plug, but no visible damage to any of the gears or bearings, except a few lines and pits in the front bearing and race. The only people who've ever touched this truck until me were Dodge, so there is it.



Oh, pilot bearing was there. The needles appeared loose, and the grease dried up, but it was intact. The throwout bearing was gone. Stacked up. I'm not sure how he drove it here. I couldn't have stood it. The DMF had red dust all over it, with lateral as well as rotational slack. I can move it several 16ths by hand laterally, and it will rotate around 1" back and forth. The pressure plate looked fine, as did the clutch disk. The fingers in the pressure plate were worn quite a bit. The replacement clutch has quite a few miles on it, but you can see most of the machine marks on the flywheel, so it doesn't appear to be abused. It drove well this afternoon after reassembly, with no vibrations, and only the slightly louder transmission noises you would expect to hear. Considering the rubber boot on top of the transmission, and the upper rubber boot in the cab on the shifter were torn pretty bad, I can't say it's very annoying. There was one screw in the entire interior lower section holding it all on the floor... . Pretty sure I fixed the customer's complaint about heat not getting to the rear floorboard, too. Looks like most of it was going down instead of back.....



I drove it 40+ miles trying to diagnose DPF issues, now. Appears the DPF is ashed, not sure what I'll be doing now... . I acquired a recent contact who says he can clean/repair it much cheaper than Dodge... . We spoke briefly this afternoon right before he closed. I'll be taking it to him in the morn. Customer wants it fixed, but I'm tired of this project... . Should have been out of here last Tuesday, and now looks like I'll have it another week. :{

 

[RVTRKN]

HHhuntitall, it sounds like, in your opinion of the condition as you found it in, was due to poor workmanship, besides the DMF failure. I will be having my G56 tore down and inspected by Richard at Standard Transmission in Tucson AZ, and the SBC DD 3250 & SMF installed, around mid May, if there are any recommendations besides the usual items that require attention, I would be interested. I have the ability to do it myself, but I am leaving it to the pro's, only because the time involved and the fact that converting it to the SMF will require some experience with the conversion in the job. I believe the two companies involved are reputable and I'm confident the job will be done right.

 

[EricBu12]

When I bought my 09 new, I was hearing of the problems of the G56 and went with the 68 RFE. auto. So far no problems with it. . towed heavy and 40K miles.

 

[HHhuntitall]

The only common problems I'm seeing with the R68 are valve body failures, on trucks that aren't used extremely hard. I've got a shop I send my customers to for the auto work, and I go by and talk with the guy on occasion, so see what's breaking, and what I can do maintenance-wise to help prevent it for my customers. Valve bodies are the big problem, it seems. The solenoids fail, but aren't easily replaced. Kenny is keeping several valve bodies on the shelf, rebuilt. This helps him with time, and gives a fast turn around for the customer.



The flywheel and clutch disk:

 

[HHhuntitall]

HHhuntitall, it sounds like, in your opinion of the condition as you found it in, was due to poor workmanship, besides the DMF failure. I will be having my G56 tore down and inspected by Richard at Standard Transmission in Tucson AZ, and the SBC DD 3250 & SMF installed, around mid May, if there are any recommendations besides the usual items that require attention, I would be interested. I have the ability to do it myself, but I am leaving it to the pro's, only because the time involved and the fact that converting it to the SMF will require some experience with the conversion in the job. I believe the two companies involved are reputable and I'm confident the job will be done right.

Poor engineering, as stated by so many before me. Ford tried this in the early '90s and suffered a lot of loss in a few years, and finally did away with it. Apparently, Chrysler thought they were smarter than Ford. I don't think replacing a factory flawed-design clutch with a factory flawed-design clutch is a good option. What's the definition of insanity??!?



South Bend is who I've been using, mostly due to my experience, but there are other good options out there, such as a Valeo solid flywheel replacement, designed for factory power levels, and I'm sure GCroyle can suggest something his company provides, all of which would outlast and outperform anything Dodge will use. My suggestion is to buy an aftermarket clutch and have it installed by a reputable shop outside of Dodge.



This is not the worst DMF failure I've seen, but this is the only time I've had time to post anything. I've limited experience with the G56, myself, and have never torn down one that wasn't exploded. But after tearing this one down, they appear to be a well designed transmission on the inside. The casing is the big reason they fail, just as Mr. Patton discussed in issue 71? of TDR. I didn't take many photos of this one, as there are plenty of exploded pics to look at in various places, and this one was mostly just dirty, nothing surprising. I'm curious what it would take to design a cast iron casing to replace the current thin aluminum one.....

 

[cerberusiam]

The engineering theory behind the DMF is solid and well known. The problems happen when the engineering diagrams are translated to actually building the parts and materials used. If they would build the DMF to medium duty standards the problems would all but disappear. Thats not happening in and LD truck for cost reasons.

The DMF addressed 2 main areas of weakness in the G56, TQ rise shock load and torsional harmonics. Neither of which the transmission likes or tolerates well. The further refinements are the viscous damper in an attempt to minimize the loading of the DMF and the failures it suffers. The G56 is a solid transmission but it does NOT like high shock loads and vibrations. Stuck with a poor design for the DMF or lack of strength in the transmission. , not a good choice to be found.

 

[RVTRKN]

I will be having my G56 tore down and inspected by Richard at Standard Transmission in Tucson AZ, and the SBC DD 3250 & SMF installed.

I have already set up an appointment for doing just that, and will be adding oil coolers from Geno's with Mobil trans SHC DC oil to be used after the trans is inspected and cleaned. I need the extra grip, for when regen shows its ugly head and will help to hold the clutch when it surges after 2000 RPM has been reached. It has caused the current failure and I will not reinstall a DMF.



CKelley1 has lots of miles at 40K GCVW on several different G56's and has yet to have a failure, except for the DMF's, which he then installs the SMF kit with the SBC DD 3250 clutch.

 

[mfurrh55]

What would you have to do to replace the G-56 with the NV5600?, Anything major?, Monte

 

[RVTRKN]

You may not want to, they are expensive, and if you do a conversion you should buy from Standard Transmission who know it and upgrade them.

 

[Regcabguy]

I seem to remember something about Standard considering an iron clone of the G-56 case.

 

[HHhuntitall]

The engineering theory behind the DMF is solid and well known. The problems happen when the engineering diagrams are translated to actually building the parts and materials used. If they would build the DMF to medium duty standards the problems would all but disappear. Thats not happening in and LD truck for cost reasons.



The DMF addressed 2 main areas of weakness in the G56, TQ rise shock load and torsional harmonics. Neither of which the transmission likes or tolerates well. The further refinements are the viscous damper in an attempt to minimize the loading of the DMF and the failures it suffers. The G56 is a solid transmission but it does NOT like high shock loads and vibrations. Stuck with a poor design for the DMF or lack of strength in the transmission. , not a good choice to be found.

And on that note, adding a better oil, using a solid clutch, not allowing our trucks to lug at lower rpm in a high gear, and downshifting to keep the torque hammer reduced is all the option we have at the moment that I can see.

What would you have to do to replace the G-56 with the NV5600?, Anything major?, Monte

I'm not sure on the later trucks what's involved. I would think it would require some driveshaft work, but that's about it. OH, and rewiring the reverse light switch.



The problem is finding an NV5600. They are hard to find, just for that reason... ... If I had a 1,000 of them, I could sell them in less than a year, I have no doubts... . I get calls every week to see if I have one. Everyone wants to upgrade their NV4500 or G56.

You may not want to, they are expensive, and if you do a conversion you should buy from Standard Transmission who know it and upgrade them.

I'd politely disagree with you on that. I've had two trannies rebuilt by Standard, and had several rebuilt for customers, and I won't let them do another. The current NV5600 in my '97 is howling like it's got a cat in it. Granted the engine makes a lot of power, but it still shouldn't be going away in less than 60k miles. Another one they did wouldn't shift, and when I tore it down, all the synchro's didn't get replaced, as well as two needle bearings. All of them make excessive noise, as if they weren't set up properly, or worn bearings weren't replaced.



I can be at Standard Transmission in Fort Worth in around an hour. Instead, I drive almost 3 hours(or have delivered) to Blumenthal's in OkC. I've only had one transmission that was questionable, and I've exchanged and bought quite a few from them. They have their own oil formulated exclusively for the NV4500 and NV5600 to help prolong their service life. I haven't used Standard in over 4 years, so perhaps things have changed? I don't think I want to gamble on it... .



Now, if they make that Cast Iron casing, I may be interested in resuming business... ...

 

[cerberusiam]

And on that note, adding a better oil, using a solid clutch, not allowing our trucks to lug at lower rpm in a high gear, and downshifting to keep the torque hammer reduced is all the option we have at the moment that I can see.

I am sure you are familiar with the observation "some people can break an anvil in a sand box..... " :-laf Engineering can NOT account for the loose nut behind the wheel, no matter how hard they try.



The marketing doesn't help by advertising peak TQ at 1600 rpms. SOME just can not an will not grok the difference between glitzy pictures and marketing spin as opposed to as-installed real world applications. The DMF is just another example of the manufacturer trying to blur the line between drivers and operators to appeal to the largest segment possible.



It is so annoying to spend $60k and be forced to deal with all crap catering to the least common denominator.

 

[EricBu12]

What about an Eaton manual like an 8 speed?. Should be a med. Duty manual out there to work with the 6. 7... .

 

[cerberusiam]

What about an Eaton manual like an 8 speed?. Should be a med. Duty manual out there to work with the 6. 7... .

The med duty transmissions are too large. They don't fit the frame, body, or anchor points. Most medium duty transmissions use a mid mount and then there is the issue with tcase connection for the 4x4's. It can\has been done but it ends being so specific to an owner that few other people will consider it. Most people are not keeping these trucks until they go to the slavage yard, preserving resale has to be considered.