This thread is to help others like me who were always wondering what the hell the DMF (dual mass flywheel) is about.

Its a spring loaded 2 piece flywheel.

Here are 2 pictures showing one of the bad parts of the DMF.

You can see how much slop my DMF has in it by the relation of the 2 pennies in the photo's.
The pennies are not moved on either picture, I actually rotated the flywheel.

Some report even further movement of the DMF.

 

Here is some pictures of the DMF to show you somewhat of how it works.


It has springs to take up the vibration of the system, but the springs fail which will cause problems like in the previous pictures as well as vibrations from the flywheel being out of balance and having flex in it where its not supposed too.

 

I am going to attempt to disassemble my DMF to show further how it works.
Stay tuned.

 

I'll take pics of my DMF when my trucks done, We'll hopefully see some carnage because I had bad vibrations as well

 

mine looks physically fine, but you can flex the mating surface to the side and turn it.

 

Found this somewhere .. some good information on DMF and why they fail.

The dual mass systems are designed to transmit less engine vibration to the drive line, and give a better more car like driving experience. They also reduce some of the jarring and stress on the transmission and remainder of the drive train. They work fine as long as the engine remains unmodified and the vehicle is not used/abused beyond manufacturers recommendations.

As soon as you start to increase the engine power over stock, or load the vehicle beyond design parameters, you run into problems. Dual mass flywheels are tuned systems and must be matched to the engine torque curve, engine resonant characteristics, vehicle load curves (including axle ratio/tire size calculations). They work by having a set of springs inserted between two rotating masses (thus dual mass). The springs are sized to soak up some of the resonant vibration from the diesel engine under load conditions. A dual mass fly wheel generally also contains an over torque friction release, so if it gets suddenly overloaded, rather than damage the springs, it slips. This works fine as a safety valve, but if it does it much it burns up. In short, overloaded they burn up and the springs get destroyed and they are worse than if it were a single mass FW.

The single mass part WILL tend to transmit more engine pulse (vibration) to the drive train, and will seem a bit rougher. But it is straight forward to design a single mass flywheel and clutch package for pretty much any engine torque curve and vehicle loading combo you can come up with. Drives more like a TRUCK, but has much better reliability at extreme use levels.

 

Had you considered modding it and making it a SMF?

 

rep sent. Keep up the good work

 

You can't really "mod" it and make it an SMF.

I spose you could weld it, but that would be something you'd do for last ditch effort to get home.
Its a failed system for trucks, thats why they dont make DMF's anymore to replace them.

 

hmmm I didn't know that they don't even make them anymore. Learn something new every day I guess, to bad it isn't in school that I am paying to go to hahaha

 

they do still make DMF's for these trucks i thought???? they are just very expensive to replace. i know the newer trucks have them. my mom's '08 6.7 cummins with a 6 speed has a DMF and has made noise since it was new. start letting off the clutch, get a little load on it then push it back in and it will pop a few times. it's funny as hell!!! that truck needs to get a SMF as soon as i know Dan is making them. LOL. i'm not buying it though. haha

 

hahaha, well now I don't know if I learned ANYTHING today.... awsome lol. Well actually I learned some about the motor today that is more than good enough for me.

 

got that right!!! motor work is always good when planned far enough ahead!

 

ya I like knowing in advance that I'm going to need a small loan to get chit done hahaha. Instead of 2 days before a trip and breaking something and saying FML then haha.

 

a small loan??????????????? (insert poking emoticon here..)

Sorry for the slight hijack there Bill, just can't help it sometimes.... ok all the time..... forgot to call u back today man, sorry. holla at me tomorrow.