dual mass??? single mass???

[allczns]

OK, I admit I've been driving automatic transmissions for too long...(E4OD's and C6's).
found an '89 F250 4x4 with a manual trans...
but folks here seem to despise the dual mass flywheel. Why? Didn't some bright young engineer at Ford think it was a better idea?
So...looking to educate myself here...can anyone point me to some info on this topic please.
thanks,

 

[Alex S]

OK, I admit I've been driving automatic transmissions for too long...(E4OD's and C6's).
found an '89 F250 4x4 with a manual trans...
but folks here seem to despise the dual mass flywheel. Why? Didn't some bright young engineer at Ford think it was a better idea?
So...looking to educate myself here...can anyone point me to some info on this topic please.
thanks,

its a combination of a bad idea and a piece of crap

 

[jperecko]

The good thing about it is that it smooths down some rollover vibrations at low RPMs... the bad news is that the 2 masses separate and cease to work the first time you stress the clutch to the point that it slips.

 

[RLDSL]

its a combination of a bad idea and a piece of crap

All rolled up in a ****
Seriously, the DMF was put in to get rid of vibration so people wouldn't have to feel like they were driving a truck The design works great on BMWs, but it is WAY too wimpy for something that pulls heavy loads, especially with it's built in failure mode if you push it too hard where it leaves you dead in the water or spinning and slipping for no reason( been there done that got the friggen t shirt )

Switching to a SMF takes care of the problem, if you stay with an 11" clutch you only get 4 or 5 springs and a lot of folks complain about gear rollover noise, but if you go to a 12 1/4" flywheel/ clutch setup. you wind up with about 9 center hub springs and no rollover noise If you call Ft wayne Clutch They'd be able to set you up with a flywheel and a kevlar pilot bushing and a rebuilt hustler Kevlar clutch and they are simply wonderful . Pull great and are easy on the knee. Really great folks to deal with.

 

[f-two-fiddy]

170k miles on My OEM DMF. If Your a heavy tower, prolly go with RDSL's suggestion. Otherwise, I've had great results with the DMF. I haul 1000-1800 in the bed/rack, daily.

 

[Agnem]

There probably was some bright engineers involved in making it. There are over 50 individual pieces in a DMF! Each one precision designed, with somebody sweating over a hot drawing board getting pencil lead and eraser dust on their fingers. AND... I would be willing to bet the thing was designed... and redesigned.... and tweaked.... and probably a whole team of people wrestled with the thing until they were blue in the face from looking at it. The reality is, it was a huge engineering effort to do one simple thing, and that is to make an alluminum transmission quiet at idle. Because the ZF doesn't use "a real man's gear lube" like the stout case iron T-19 does, there is nothing to keep the gears from bouncing off each other at low RPM with no load. So a SMF on a ZF sounds like an orbital floor sander on a hollow body guitar. Most of us that prefer the simplicity and reliability of the SMF and live with the noise.

The good news however, is that soon a 3rd option will be available! Check it out!

 

[THECACKLER]

My DM setup has served me well. It was replaced approx 150-200Kmi. ago by the previous owner who often a pulled 20K GN trailer. That's beyond the design limit and can't be faulted to the Flywheel Designers. I have slipped mine once by my own error and probably heat checked the flywheel by doing so, but it performs very well pulling an 11K trailer.
I am going to swap it out for a 12-1/4" SM when I replace my engine simply for the fact that have it in hand and believe I will be ready to refresh the friction disc. The disc is from Dial-A-Clutch and is stamped LUK and printed with Valeo and their part designators. It has 10 sets of springs (inner and outer) making 20 springs total and the friction material appears to be carbon fiber.
Incidentally, I have heard that the DM setup is only required for the 5 speed ZF. Apparently the 6 speed version is fine with a SM flywheel. I wonder what was changed to offset the rollover rattle.

 

[65sixbanger]

I think youre right about the six speeds having a SMF, my bosses 7.3 sounds and feels like a SMF.

Also the DMF on my truck has so much play its ridiculous, I know I need to do the Lucky mod just dont have the time to pull it. I might weld it for now...

 

[allczns]

thanks!

...as usual you guys have cut straight to the heart of the matter...
so the DMF was a misguided effort...somewhere there was a director of engineering who let this one get off the rails. Where was Bill Ford when all this was going on???

so an SMF will not turn a ZF into scrap aluminum?

Mel, where can I buy a turboencapulator???

 

[RLDSL]

You're killin' me Mel

 

[Agnem]

I believe that was a Rockwell product. That would be cool... a Rockwell transmission behind our IDI's.

I've been running lucky modded flywheels without incident for I think about 5 years now. I also use 2 gallons of streight 30 wt. motor oil instead of ATF as my trans fluid.

 

[RLDSL]

Ford had nothing to do with the design, It's a ZF thing. THey used them on cars just fine. Like I said, They work great on BMWs, make for a real incredibly smooth setup for driving in traffic , but the idea just didn't translate well into something this heavy duty.
I've always wondered about the lighter load rating on the manual tranny trucks I'm not sure but I'm thinkin that it might have something to do with the overload protection device in the blamed thing is the limit factor. I can't see any other reason why you would rate a slushbox higher than a manual tranny. and after having had one of those things cut loose, I can understand why., otherwise I would think a solid coupling would have a higher rating

 

[Rot Box]

My DMF is a love hate thing.

Love it in the Utah rocks at very low speeds crawling around bouncing back and forth. It smooths out the clutch work enormously compared to diesel trucks that don't have that feature.

Hate it because it rattles, clanks, creaks and all around sounds like its going to explode when I'm idling in neutral and judging by my records its only a few years old

That said I will probably buy the best SMF that money can buy when my engine blows or the clutch lets loose which could be any day now

 

[mahatma171]

My DMF is a love hate thing.

Love it in the Utah rocks at very low speeds crawling around bouncing back and forth. It smooths out the clutch work enormously compared to diesel trucks that don't have that feature.

Hate it because it rattles, clanks, creaks and all around sounds like its going to explode when I'm idling in neutral and judging by my records its only a few years old

That said I will probably buy the best SMF that money can buy when my engine blows or the clutch lets loose which could be any day now

Dad's old 89 ECLB F250 always sounded like Santa Claus was coming... (jingle bells) Well, we ended up pulling the engine after a busted headgasket and mild hydrolock. That old dual mass contraption was only hanging on by a spring or 2 and ready to fly apart, anytime.... Replaced by a SMF and, IMO, thought the ZF5 drove and shifted so much better than it did with the DMF setup.

 

[THECACKLER]

I've always figured that the higher rating for an Automatic was due to the Torque Converter.