Dual-mass flywheel failure stories

[C.K. Piquup]

I`ve had my second bout with the dual-mass flywheel and once again I`ve lost.This time the symptoms were different and it makes me wonder how other members have experienced DMFailure.On my`92 I was unaware of the DMF.The truck made a rattle noise while sitting in neutral,like a throw-out bearing.With clutch pedal depressed thenoise stopped,thought it was the input shaft bearing.I drove it forever this way.Finally went to fix and that`s when I met my first DMF.Most of the rubber cushions were gone,the rest shot.Now on my`95 I had 6,500mi.on a new motor when I started hearing a noise more like a knock.By the end of the day it started making a racket that sounded like the bottom end was coming out of it.I shut it down,towed it home,did an oil analysis,and found no particles.Also oil pressure was reading normal,but I didn`t trust that.You can`t pull the oil pan w/o pulling engine and I really didn`t want to do that again,unless absolutely necessary.I pondered and asked alot of questions.Then,"BAM",it hit me,DMF(not me,the flywheel).Pulled the T-case and tranny the other day and found the DMF came apart and front section was eating into the bell-housing.Totally different experience both times.Anyone have another version of DMF failure to share?

[CleviteKid]

Hey CK, the DMF comment had me laughing out loud. Perhaps the DMF title should go to the so-called engineers who designed this junkassembly without even doing a quick mental Failure Modes and Effects Analysis. Probably the same guys who did such a great job designing the 1982-1984 glow controller that they got promoted to drivelines. :rolleyes:

Thanx for the laugh, Dr. Lee :cool:

[rjschoolcraft]

The bad thing is, they were probably after a pretty good idea...just poorly executed. The FMEA is a critical part of any design analysis, but gets left out far too often. Especially, if the folks doing the design don't have much practical experience. A lot of very good ideas have been doomed to the scrap heap for this very reason.

A similar line of reasoning led to the "isolator crank pulleys" on these engines. The reduced dynamic loads in the belt are a good idea, but how many crank pulleys failed before that idea? NONE! It would be better if they listed it as a maintenance item with a scheduled replacement, but they didn't even tell anyone about their new failure mode introduction.

[radrecon69]

Got one of those Dual Mass flywheels sitting in the back of my truck if someone wants it I upgraded to the solid mass flywheel

Rick smile.gif

[C.K. Piquup]

I wouldn`t doubt if GM isn`t the true DMF that possibly ignored the effects report.Hope not.I know the problems from the 6.0 Powerstroke were due to the fact that Ford rushed it to market inspite of Navistar wanting to give more time to testing.I`m glad GM didn`t do that with the Dmax,...right?My brother-in-law and I make"Junk Monsters"from scrap/junk.I know where my DMF is going.Hopefully I`ll get back some of the expense of the conversion.Rich DMFs`ll pay as much as $1,500 for these...things.

[rapidoxidationman]

Around 110,000 miles my truck would start to vibrate intermittently, particularly just when I started it up then it would feel great. Sometimes revving the engine would make the vibe go away until I started it up again, sometimes not. I thought I had a clogged injector or some such. Just to be safe I changed the crank pulley and the harmonic balancer, after reading horror stories about busted cranks caused by rubber failure of these components. Then one day... around 120,000 miles I was at a light and the vibration started. I hit the gas, no change. I lugged the engine - started it in third gear...wrong move. the vibe got really bad and wouldn't go away. Limped it home, brought it to the guy who charges lots of cash to look at. He dropped the tranny and found the two parts of the DMF to be eccentric to each other, caused by more than half of the bearings that separate them being missing. The two halves were locked this way. I'm lucky it didn't destroy my bell housing, crankshaft, motor mounts, me... The bill came to almost $2,000 with a new single mass flywheel, input shaft to the tranny, pilot bearing, slave cylinder, clutch, rear main seal, and labor. The only beef I have with the single mass is the chatter going into reverse and sometimes chatter starting in second gear.

Beware the DMF bearings.
Rapid

[C.K. Piquup]

My truck is fixed (adapted),now.I`m so happy to have had the opertunity to sink another $2,000 into this truck.Though,I wish it was for an inter-cooler,or rear disc-brakes,or GearVendors/OD,or...But I am now a member of the SMF club.No more hanging my head when asked which club I`m in and replying in a mumble,"DMF".Now,I just look`m straight in the eye and say boldly,"SMF"!!

[CleviteKid]

Seems like that would be the "Smart" thing to say :D .

Dr. Lee :cool: