Dual Mass Separating?

[jclark5810]

My father in law has an 06 with the G56, it has an awful rattle at shutdown which to me sounds like something coming loose? If the flywheel is "separating", is this something you can physically hear? He doesn't notice it but I can definitely hear it, don't want to mention it though and have him worrying about nothing if it is truly nothing. Doesn't have any symptoms of clutch issues other than that chatter/rattle and shutdown. Thanks in advance for any insight.

 

[jelag]

The dual mass flywheel usually give problems before the clutch...

The flywheel has plastic parts that hold and align some of the parts. . It's usually the plastic parts that fail from heat. . In all the ones we replaced we pitched the dual mass and installed a solid flywheel with a different clutch. Gary from Perfection Hy-Test did an article on one of the replacement clutches available. You should be able to research this in back issues.

 

[jclark5810]

Thanks Jim i appreciate your help. I'll track down that article. So you'll start to have symptoms would be a stiffer pedal, increased noise during operation? Will the flywheel sound like a bucket of bolts when shuts down?

 

[CKelley1]

change it out now before it damages the g56. get a southbend conofe kit. i can not believe it lasted this long. when you pull the g56 out check the front seal the dmf usually causes the front seal to weep oil. get one gallon of synthetic syncromesh sae50 transmission fluid and one gallon of 5w-30 synthetic syncromesh transmission fluid and mix them together fill 7 quarts in the g56. this is one quart over full and is easy to do while the shifter is out. brand is not critical, royal purple, amsoil dello, delvac, shafers and many others make it. save the last quart for when the red boot on the shifter fails you can add some makeup to it. the new southbend will be noisy compared to the dmf. the aluminum g56 transmits engine noise the dmf killed.

 

[GCroyle]

Joe PM sent.

 

[jclark5810]

Thank you CKelley for the insight, I appreciate it.



Gary I watched those videos, they are excellent. Thanks again for the help!

 

[jclark5810]

Also forgot to mention Gary, your attention to detail and workmanship are top notch and make me wish we were closer to your shop. However we're making progress, going from a 5 day drive to a 5hr drive here in August:-laf

 

[GCroyle]

Joe,



Appreciate the kind comments. What we found was the likely noise source for KLaubers truck, you may have a different cause. Attention to detail is critical to pretty much everything, clutches need it too.



Regards,



Gary

 

[jclark5810]

So I went over there this evening (He's out of town), and started it up and shut down multiple times. With the clutch pedal out, the noise is clear and present. With the clutch pedal pushed in, transmission in gear, the shut down, the noise is definitely still there but not as prevalent. It almost sounds like metal swishing back and forth almost a complete second after the truck has shut down. I'm going to discuss the issue with him this weekend when he get home. Does that sound like a flywheel or am I creating something out of nothing. Truck has 80k miles on it, only gets driven on the weekend for 400 miles all empty.

 

[GCroyle]

Joe,



I think shutdown can be an almost violent event to the previously running engine. The DMF is shaking the secondary back and forth like a dog with a toy in its mouth. The springs in the DMF are compressed and extend vigorously. Possible that a spring is failing, can't tell w/o inspection of old part. I have old video of a 7. 3L DMF at shutdown and it is shaking like crazy, it was also worn out.



IF you can control it a bit as you describe, it may be possible that the disc is also in a failure mode and the damper is allowing the trans to shake rattle and roll also.



Guys, don't take this as DMF bashing, we're trying to help Joe diagnosis his question in writing, a bit challenging. And here at work we also offer the DMF for these trucks, it's your choice.



Good luck Joe.



Gary

 

[jclark5810]

Thank you very much Gary, it is exactly as you described. In fact, I assumed that's what the noise was before I even began digging around. I had an old IDI F250 that had similar symptoms before we converted to single flywheel. I'll talk to him this weekend and PM you if I need to get a clutch kit. Thanks again!

 

[AH64ID]

My dad's 06 has always rattled at shutdown much more than my NV5600 has. It's part nature of the DMF and part becuase the G56 is aluminum and transmits sounds better. His DMF now has 90K miles on it, many of which are towing 10K+. We just put a 6. 7 harmonic damper on it and nearly all of the shutdown sounds are gone.

It could be normal, and it could be the DMF failing. Hard to tell without getting it looked at. But if your not used to a DMF the initial sound of shutdown is that something is wrong when it may not be. Odds are good at 80K that it could be at the end of it's life.

 

[Regcabguy]

I always minimized the dmf shutdown sound by depressing the clutch and leaving it in neutral when shutting off the engine. My Fluidamper did next to nothing to improve on that procedure. What killed the noise was the aftermarket smf conversion.



According to the installer,my stock clutch was like new at 37K. 34" tires,Smarty on #3 and a 2000# camper load didn't adversely affect it. If I didn't have a slight rear main leak,it would still be in there. I would have left it in for 20-25K more.

 

[JRutledge]

My flywheel separated at 160k with the original clutch. The only notice it gave was a vibration at idle. The last straw was putting my edge module on 5. I still limped two miles home.