SMF stressing the trans?

[Mulochico]

I am looking at going to an SMF in the future. I was at the local dealer for other things and asked about parts for the switch. The parts guy said it is a bad idea, and when asked why he said one of the mechanics was against it.
I did not talk directly to the mechanic, but the parts guy checked with him and came back with "diesels have a more off/on power and this will cause undue stress that a DMF is designed to help eliminate".
Has anyone heard of this or had problems when doing the lucky mod or SMF? I just want to know what I am getting myself into.

Thanks

 

[oldmisterbill]

I think he may be refferring to the impulses of the high compression (which is also what makes the belts vibrate). In my opinoin only -if you think of the on off foces when you decerrerate and accelerate ,there is no comparrision. ZI personally wouldn't worry except for the racket. I drove a 1978 Mack for years it hed 2 1/4 million miles on the origional trans when the company went under. Talk about gear rollover noise! That old Mack would rettle your teeth when idleing -and it sometimes idled for hours.

 

[typ4]

there are springs in the clutch disc in the single mass conversion to do what the dual mass flywheel does.
And it was just for the american buyer to not here noises from the trans and panicking, I have never seen an over the road truck with a dual mass flywheel and most have solid discs.

 

[Goofyexponent]

I think he may be refferring to the impulses of the high compression (which is also what makes the belts vibrate). In my opinoin only -if you think of the on off foces when you decerrerate and accelerate ,there is no comparrision. ZI personally wouldn't worry except for the racket. I drove a 1978 Mack for years it hed 2 1/4 million miles on the origional trans when the company went under. Talk about gear rollover noise! That old Mack would rettle your teeth when idleing -and it sometimes idled for hours.

The L9000 I ran had some BAD gear rollover noise.....15 over and it had almost 1.6 million Kilometers on her!

 

[Mulochico]

I am a professional truck driver also (27yrs ) so I to understand those forces on parts. The on/off pulses is exactly what he was referring to.

Semi trucks are designed for those forces, he was trying to tell me that the ZF was not and the stress would tear the trans up. I had not heard of this before so I thought I would throw it out there to the most informed IDI people I know

 

[DragRag]

A dual mass factory set up has a solid clutch disc. A single mass uses a clutch disc that is sprung, either way the same objective is achieved. Now either this "mechanic" is misguided, or the dealer parts guy really wants to sell you some clutch parts since he can't get a single mass for you. The things people make up to look smart, or sell parts makes me laugh.

 

[franklin2]

During one of our many discussions on the factory DMF, it was determined the factory DMF has two sections to it.
1. Is the section with the springs and clutches everyone is familiar with that oscillates back and forth to cancel out the pulses of the diesel engine.

2. Is the clutch plate section down deeper into the DMF that slips at a predetermined torque level. This was added by the engineers to protect the tranny, apparently the zf was not rated heavy enough in their eyes to take everything this engine could dish out.

That being said, I don't think I have read that anyone has ever broken their zf yet with a SMF flywheel, even with lots of boost from a turbo, though I believe I read some have had that section in the DMF start slipping on them when they still had the factory DMF and a high output engine.

So technically the mechanic is correct, but in real world application there does not seem to be a problem with using a SMF.

 

[typ4]

I dont think in my professional mechanic opinion that the single mass will hurt the trans unless you are really ******* it.
If it was I wouldnt have used one in my truck. And I drive it pretty hard.

 

[icanfixall]

Wheres Calvin when you need his oppinion.... I have never heard of a smf ruining a zf .... About all you hear on this forum is how much better the trucks are with a single mass clutch as compared to the double. Parts continue to fall out of the dmf all the time on this board. The lucky mod is drilling and bolting together the duals to a single mass clutch. Plenty of members have done that without any issues. Being a holiday weekend we have lots of the guys at the rally so wait around for more first hand posting on this topic...

 

[Mulochico]

I thought that they were "less than accurate" (to be nice ) in their assessment. Just thought, since there are more people on this board that know their stuff, I would check.

Thanks all