can the dmf slip like a clutch, or just rattle? if the dmf has no play when flywheel is turned by screwdriver and the springs are not loose, how much chance is there that it is good. replaced clutch, pp, tb 4-5k miles ago and not always but sometimes have clutch slip in 4-5 gear. can't figure it out. thanks.

 

The flywheel can't slip, but the clutch can.
From your description it sounds like your dual mass is fine.
Specs say replace if you have 5/8" or more free play in the flywheel.

 

thanks dave, maybe got a bad clutch disc. never put much strain on this one. it should still be good. the dmf looked to be good, no play. well i guess pull the tranny and see. thanks again. rob

 

was just reading on "clutch city online"website that the flywheel CAN slip...there is supposedly a friction disc between the two parts of the flywheel that can wear out...

I have a '89 f-250 diesel 5 speed and the springs on the engine side of flywheel are breaking in pcs...Ill get 1 and 2 turns of the spring scraping around in side the inspection cover every now and again...so I took the cover off and now they just fall out....BUT ....the fact remains theyre disintegrating and at some point Ill have no springs.

ANYBODY know of an outfit that either rebuilds these dual mass flywheels ...OR sells the springs????

My truck is old and Im not really too keen on spending the bucks for a LUK

someone told me worst case you can weld the 2 halfs of the flywheel together along the seam where they meet...probably not gonna be too kind to trany though...since protecting the tranny at idle and low rpm is what the dual mass is for in the first place - side benifit is acts as damper when releasing the clutch - to drive away from position of rest

other alternative is maybe using a 545 ALLISON from a schoolbus and a divorced transfer case...that would be different....thats a hell of a lot of work though.....I dont know what to do...the truck is sweet except for this Ford masterpiece of engineering.

any suggestions/comments welcome

 

a dual mass flywheel does indeed have a friction disc that looks and acts like a clutch disk. and when it goes bad, it will act just like a bad clutch that is slipping.

as you drive it, the friction disc gets hot, then overheats and slips in 4th and 5th. eventually, it will get so hot that you will not be able to use 5th gear. and if you have a turbo, it will get worse faster. the fix for this is to convert to the luk clutch setup. everything you need, the flywheel, disc, pressure plate and throwout bearing is less than half the price of a dual mass flywheel alone.

 

Buffalobob, why would you mess around with the dual mass clutch....from all that I have read, they cost a fortune to replace, while a Luk replacement clutch is cheaper and more reliable, just a thought.

 

I have welded dmf and used synthic 90 wt. in the 5 speed with no problems. I have also used a 6.9 flywheel ( solid ) drilled and taped for 7.3 pressure plate using luc revision plate and disc.

 

fordtks....how much and where did you weld the flywheel?...and how does it work when yuou are starting from a stop?.....doesnt the clutch GRAB bigtime being that there are no springs in disc and flywheel is now solid?...interesting because I really dont want to tear this down and spend around $700 for the Luk parts...the labor is no duckwalk either...

to clarify the other option...a 6.9 has a solid flywheel and you drilled and tapped for using the Luk 7.3 pressure plate and clutch disc...is that what I read?...why did you go to synthetic 90 wt???..instead of sticking with Mercon ATF?....Im in Buffalo NY...gets pretty cold here for me to try that...

wonder if I could weld the dual mass togther and make solid and then use the LUK press plate/disc the same way????

 

I used synthetic 90 because it doesnt get thick and heavy like straight 90. Synthetic allows shifting in cold weather.You only need to use the 90w when welding the dmf. The 90w takes the gear rattle out.I live about an hour below Syracuse, It gets cold here too! Yes to the revision clutch and plate on drilled 6.9 flywheel.The flywheel that luk uses with their clutch pact is the same as the 6.9 with 7.3 bolt partten. I got this info from a gentleman out west that builds clutches. . I have his number written down somewhere? He also told me that the old 392 gas flywheel is the same. In welding the dmf, I C- clamped both haves together, welded in 4 places across from each other about 1 inch welds. If it looks like the springs are going to fall out or if they allready have started, do yourself a favor and remove the rest of them. I have used the welded dmw in a 450 dump ,over 30,000 miles, no problem. I used the Luk revision on my drilled and taped 6.9 flywheel in another 450 dump atleast 30,000 miles , no problem.

 

Buffalobob, Forget two things. The clutch does not grab. Dont know if you can use Luk revision on welded dmf. I have heard tell someone welding the dmf in the truck, go for it. Might save time and money.

 

If you don't switch the clutch disc to a spring type, you run a good risk of breaking other parts. The springs are there to protect the engine and trans from sudden shock loads. You can use the LuK disc I have been told.

 

thanks all...Ill ponder what to do.

I would STILL like to know if anyone has a source for the DMF engine side SPRINGS....If they and the little do-hickey things that go on the ends are avail...I wouldnt hesitate to rebuild this flywheel with those parts.....I called Buffalo Clutch ..here in Buffalo...they want like $350 to rebuild the DMF...so parts ARE avail.....probably have to be in that business though...they wont sell the parts ...they want to make the big cake $$$$$$ and do the job....

anybody that has done it KNOWs that taking the transfer case and trans out of a 4x4 to do a clutch is a PITA job...the LUK cost is not a good investment in my opinion...for this truck...I rather sell and buy something else if I cant fix cheap....

 

Fellro86, The real question here is, Why didnt they need a dmf before the 5 speed zf?In another forum on this site, someone tells about documentation of not mix matching 6.9 and7.3 flywheels and engine dampners. Both engines are internaly balanced. What difference can it possibly make?

 

The design on the ZF apparently is such that it echoes some harmonic noises that can be heard through the trans, while the T-19 didn't resonate the same way. I have seen the statements about not switching the DMF and SMF setups, but like you say, external balance, so it shouldn't matter. You will hear it go both ways. I don't know the full answer there. I did help with a LuK conversion, and they were happy with it, didn't recall the noise that is talked about, and they never commented about any noise.