G-56 guys, CLUTCH UPGRADE!! No more DMF!

[South Bend Clutch]

Thank you SBC for this extensive history... However, I thought it was time to "clear the air" on the whole DMF/G56 debate:

1. ) The DMF was requested by DCX, not "decided" by LuK

2. ) The DMF is not responsible for the added drivetrain lash. Extensive testing has been done to verify that tip-in/back-out lash is linked directly to trans/transfer case/propshaft/axle windup, not DMF slop.

3. ) The DMF does an excellent job of isolating engine fluctuations from reaching the transmission. For you math gurus out there who understand this stuff - the engine produces upwards of 150 rpm peak to peak fluctuations per firing, while the transmission only sees 10-20 rpm peak to peak thanks to the DMF - that's got to be worth something to the transmission's durability.

4. ) The famous DMF which gave the bad name, the Ford Valeo DMF, is an entirely different design and not produced by LuK! Yes, Luk Aftermarket stepped in and replaced it with a solid mass because they couldn't fix the Valeo design to make it durable (bad design from the start).

5. ) The 5. 9L DMF is produced in the good ol USA, not Brazil.

6. ) You can thank the LuK DMF/Disc/Clutch design for that low pedal effort and smooth engagement - beacoup bucks were spent to develop it into a nice package.

7. ) And on the topic of R&D, LuK purchased multiple vehicles for the development of this package, as well as evaluating 30+ vehicles supplied by Chrysler. Some of the LuK-owned vehicles now have over 200k miles on them now - do you really trust a product from a manufacturer who can't even purchase one vehicle?

8. ) And by the way, for those of you who have heard that the DMF causes long crank times... I personally conducted the DOE on this complaint and found the DMF to have no effect on crank/cam sync time. It was theoried that it could have an effect, and I regret that the rumor was passed on to the dealerships in that manner.



Hopefully this doesn't start a flame war, but I thought it could be beneficial to hear the comments from somebody who knows this product... very well.



Red_Smoke

"Dabbling in powertrain NVH, every day of the week"

WOW, very well written. You seem to have quite a bit of knowledge so I did a search on your past history and saw that you have not posted anything in the forums since Dec. 2004 until today.



You posted this today... . "This isn't actually a pressure relief valve - it's an inline damper system for the clutch hydraulics. It's there to combat pedal vibration when engaging/disengaging the clutch pedal. If you truely have a popping noise, it sounds like there's either a release system problem, or a throwout bearing/quill binding. I have heard the clutch pedal switch snap from time to time on some of these trucks, but that noise is in the cab. "



And, you posted this today... . "The noise you're referring to here is in-gear rattle, which is a consequence of the engine torsionals being imparted to the transmission, which lights off the free gear sets in the transmission and causes "gear rattle. " Only fix for this is a DMF like that on 05. 5 and up trucks. "



But, you had posts like this a year ago... "Hi guys-

Just wondering if anybody's 6-speeds grind real bad when going into reverse? Mine never used to do this but lately has gotten bad (19k miles). I used to feel two "notches" when shifting to reverse, but now I either get a bad grinding or a "jolt" to the driveline as it engages. If I take it for warranty, is the dealership going to try to rebuild it or is it a "replace" item?"



Thanks-

RedSmoke"



And this... . "Hi guys-

The neighbor is bringing his 1999 2500 over tonight for me to "take a look at it" (aka fix it for him). He claims the truck is missing on a couple cylinders under part throttle, but doesn't miss at idle or under wide open... .



Any ideas where I should start?



Thanks-

jt"

You sure seemed like a different guy a year ago.



Peter

 

[RedSmoke]

Hi Peter et al-

You sure are a resourceful guy! Yep, I was new to the whole Cummins scene when I bought my truck in late, 03. Gotta say, I love it and would never own anything different now, which is why all of us pay the $$ to join this group of friends. However, I've been in the clutch/NVH business a long time - actually I bought my truck because I was working on the new G56 trucks in 2003, and after having spent so much time in them, knew I had to have one (a Cummins that is)!



At any rate, I'm rather non-confrontational, so instead of firing flames, I'll praise you... you're products are well-built and serve their purpose very well. However, very few truck owners are making 1200 ft-lb +, which is where I believe your products shine. The OEM DMF/SAC combo has had over 3 years of R&D for stock vehicles and creates an overall nice driving experience, especially for the brute of an engine that the Cummins is. It's not meant to transfer 1000 ft-lbs+, and this is where you come in.



My only purpose in posting my reply was to educate the masses (aka those with stock or slightly modified vehicles) as to the benefits and truth behind the DMF in our trucks. It's a much better product than the old Valeo's found in Fords, and I hate to see them get a bad name from false information posted on this site. The site is invaluable with a wealth of information for truck owners, which is why I posted those threads in 2003/4 - I'm not an expert on 2nd gen trucks like the one I spoke of - I'm just a clutch guy



Lastly, I apologize for my insinuating comment "a manufacturer who can't even purchase one vehicle?" It was certainly pointed, and I crossed a line that shouldn't be crossed in a crowd of TDR members.



Peter, as you've noticed I don't frequent the boards often, but if you have a general question regarding the G56 clutch package, I'd be more than willing to help. As a businessman, you are aware of proprietary information, and are aware that I can't cross those boundaries.



Have a great evening-

RedSmoke

 

[RedSmoke]

Red smoke, can you tell us what kind of service life to expect out of the DMF?

How much power can the stock clutch and DMF take before damage occurs?

Do you have suggested solution for the extra driveline lash? Is it even a problem?



Thanks,

Jay

Jay-

Without giving proprietary information (and I probably shouldn't be on here at all I can speak from experience that mild power boxes are OK in conjunction with the DMF and SAC clutch. Everybody here probably realizes, or should, that OEM vehicles are designed with safety factors on all parts. When you put a box on the truck which makes, say, 750 ft-lbs at the crank, you're using the safety springs in the DMF, which all in all, translates to less life. The same goes for our engines, trans, and on down the line.



If you want 1000 ft-lbs in your daily driver, and you make that kind of torque on a daily basis (aka lead foot), your DMF isn't long off. The DMF will make a somewhat noticeable popping noise when you've reached the limits of the springs, and you're essentially beating the rivets to death. It's permanent deformation, and also occurs at speeds below 500 rpm (for 06 and up trucks - 05. 5 had a fuel cutoff at 475). When the rivets break, you're dead in the water with a 2 piece DMF - 2 separate pieces



As for the driveline lash, there's nothing you can do, but hasn't been shown to harm anything (third hand information here, since I don't work on anything after trans). If anyone knows different, I'm sure they'll speak up.



Good luck-

RedSmoke

 

[hasselbach]

How about somebody make a Dual disc, DMF set up?



I think the strong torsional vibrations are havoc on everything, and tend to beat gears and other parts to death.



The DMF is nice with the reduction in the overall vibration. Coupled with a DD, and it would be a great set up. Problem is, could one be properly designed to live long enough.

 

[TCluff]

Jay-

Without giving proprietary information (and I probably shouldn't be on here at all I can speak from experience that mild power boxes are OK in conjunction with the DMF and SAC clutch. Everybody here probably realizes, or should, that OEM vehicles are designed with safety factors on all parts. When you put a box on the truck which makes, say, 750 ft-lbs at the crank, you're using the safety springs in the DMF, which all in all, translates to less life. The same goes for our engines, trans, and on down the line.



If you want 1000 ft-lbs in your daily driver, and you make that kind of torque on a daily basis (aka lead foot), your DMF isn't long off. The DMF will make a somewhat noticeable popping noise when you've reached the limits of the springs, and you're essentially beating the rivets to death. It's permanent deformation, and also occurs at speeds below 500 rpm (for 06 and up trucks - 05. 5 had a fuel cutoff at 475). When the rivets break, you're dead in the water with a 2 piece DMF - 2 separate pieces



As for the driveline lash, there's nothing you can do, but hasn't been shown to harm anything (third hand information here, since I don't work on anything after trans). If anyone knows different, I'm sure they'll speak up.



Good luck-

RedSmoke

i believe that is correct, dual mass flywheels wont survive a non stock truck...

 

[JayWm]

RedSmoke,



sounds like you're saying that it isn't gonna take much beyond stock power.

You referred to low rpm causing damage, do you mean that if it idles down too low the DMF can be damaged? Would it then be wise to hold the clutch down during shut down?



Thanks,



Jay

 

[South Bend Clutch]

Good Morning,



As to this phrase...

Lastly, I apologize for my insinuating comment "a manufacturer who can't even purchase one vehicle?" It was certainly pointed, and I crossed a line that shouldn't be crossed in a crowd of TDR members.

Have a great evening-

RedSmoke

Apology excepted





Now, I would like to nip something in the bud before you continue your crusade. You stated that our clutches shine at the 1200 ft lb. of torque and not very many people are at that level. Sir, our single disc clutches will slip at that level. This should be corrected in the next month as we are building our pressure plates to have 3400 lb. of plate load whereas the OEM LUK is 2850 lb. .

Our clutches are rated from stock torque levels through 1100 ft lb. of torque with everything covered between. I believe you are trying to convince people that our clutches are only for the insane power. To further validate my assumption I found that you also posted "Yesterday" on this thread...



http://turbodieselregister.com/forums/showthread.php?t=150354&highlight=clutch



This... You'll find that unless you're running a significant amount of torque, the LuK part will give you many more miles with a better clutch feel. The SBC clutches are well-made and serve their purpose - but unless your purpose is to transfer 1400 ft-lbs of torque, stick with the Luk.

__________________

RedSmoke

Flame Red 03 HO/5600 4x4, SJ 2" coils, B&W Turnover, Autometer Phantoms



Now, I think the people on the TDR forums are a little smarter then this. I would say that maybe 1% of the DTC people are at this level and these trucks are most likely used for competition and would require a double disc clutch. I think it is interesting that a LUK engineer has come to the forums to promote their clutches.



On to the DMF...

I believe that adequate dampening is very important for the torsional spikes produced by the diesel engines whether it be in the clutch disc or a dampened flywheel. In a perfect world, using your truck within it's ratings @ stock power levels, I believe the DMF will provide adequate life and extend the life of the transmission. Now, lets talk real world. We live next to Elkhart In. which is the trailer capital of the world. I have seen these trucks pull things that have made me cringe. The TDR members come to these forums not only to learn about their trucks but for the most part to add HP and torque. You yourself stated that the DMF was not designed to handle this. This is where we come in. We designed a solid flywheel replacement to allow the people with the G56 transmission to add power to their trucks or overload their trucks without worry of DMF failure. The clutch disc will have adequate dampening to absorb the torsional spikes created.



You stated that the Valeo DMF failed miserably. This statement is simply not true. Remember, we are the guys that see the end result from real world use. We are not the guys at the beginning on the drafting boards. Failure only occurred when the truck was used past it's ratings or there was issues with the performance of the truck i. e. bad injectors/fuel pump, etc. , or HP was added to the truck. Other wise they performed fine until they simply wore out. The major problem was when it came time to replace them. Cost to the consumer was somewhere in the park of $1000 just for the flywheel. This is where LUK stepped in. Simply reproducing what was being used in the DTC trucks and altering it a little to fit the Ford diesel trucks.



As for the DMF that LUK has developed. LUK is the OEM clutch manufacture for the Chevy Duramax. This clutch and flywheel assembly (DMF) is almost a spitting image of the assembly used with the G56 transmission. It has been in and running in the real world for a few years now. If you go to this website and do a search on clutches, you can form your own opinion on what you have in your truck... http://www.dieselplace.com/forum/index.php



I will post some pictures today of the two flywheels, Duramax/Dodge G56.



Peter

 

[South Bend Clutch]

RedSmoke,

Would it then be wise to hold the clutch down during shut down?



Thanks,



Jay

YES! This is very good advice for all diesel trucks. This will unload the clutch while the crank spikes during the prosses of shutting down.



Peter

 

[South Bend Clutch]

How about somebody make a Dual disc, DMF set up?



I think the strong torsional vibrations are havoc on everything, and tend to beat gears and other parts to death.



The DMF is nice with the reduction in the overall vibration. Coupled with a DD, and it would be a great set up. Problem is, could one be properly designed to live long enough.

LOL!!!!



This would be awesome, thought about it long ago but the DMF's available simply will not take the added torque.



Peter

 

[hasselbach]

LOL!!!!



This would be awesome, thought about it long ago but the DMF's available simply will not take the added torque.



Peter

But I'm sure you could design and make one...

 

[RustyJC]

The SBC clutches are well-made and serve their purpose - but unless your purpose is to transfer 1400 ft-lbs of torque, stick with the Luk.

__________________

RedSmoke

Flame Red 03 HO/5600 4x4, SJ 2" coils, B&W Turnover, Autometer Phantoms

My stock Luk (admittedly a 2nd generation HO clutch) slipped like mad at 762 lb-ft torque in 5th and 6th gears - with no trailer hooked up. The solution was a South Bend Con OFE.



Rusty

 

[South Bend Clutch]

Here are the pictures:





Peter

 

[hasselbach]

My stock Luk (admittedly a 2nd generation HO clutch) slipped like mad at 762 lb-ft torque in 5th and 6th gears - with no trailer hooked up. The solution was a South Bend Con OFE.



Rusty

Score so far... .



South Bend Clutch 1

LuK Clutch 0

:-laf

 

[jandr]

I've tried reading ALL the pages on this topic but admittedly may have missed something so if I ask a question that's already been answered, please forgive me

It sounds like SBC now has the fix for the concerns of the DMF I had been reading about months ago? I went to their website and saw the clutches for the G56. The MU 1947 Con series?

This all sounds good. Just wondering what the prognosis is for the rest of the transmission holding up?

I am in the process of getting a new truck, I wanted a 6 speed all along but the negative talk made me leary. So I figured I would get the auto even though I didn't really want one. Because of that, I put off buying one for a while but sort of need to do something soon.

Now that I have seen people reporting problems with the auto also and have just seen this new development(for me anyway) with the DMF issue, I am again leaning towards the G56.

I am not into huge amounts of mods. I believe the only things I would do would be a free flowing intake, a turbo back exhaust and MAYBE a box(lowest power type).

So my questions are:

1)What do the insides of this transmission look like... . are they going to hold up with this clutch/flywheel setup?

2)Do they sell direct? I went to their website and it looks like they only sell to dealers/installers. I saw their list of both nationwide. I currently live in So Cal but am planning a move to Indiana soon.

3)About how much does this setup cost?

4)What would be the disadvantages(if any) of a setup designed for higher HP/torque that was put in a truck that was only slightly above stock?



THANKS

 

[South Bend Clutch]

As for the G56 transmission we tore into @ Blumenthals. It has a lot of plusses. The shifting rack mechanism is far better. The gears are independent and double spline instead of welded on. The transmission we looked at had 70,000 hard miles with no engine enhancements. The Bearings we almost shot, better oil may be a +. The throwout brg. quill was made of tin, the previous transmissions supported a cast iron quill. Other then that, it looks pretty good. We offer direct service as well as distributor service. Prices cannot be discussed by venders on the forums.



Peter

 

[Gary - K7GLD]

Score so far... .



South Bend Clutch 1

LuK Clutch 0

:-laf

Perhaps - if no one objects to comparing a dead-stock OEM LUK against a SBC aftermarket performance replacement...

My stock Luk (admittedly a 2nd generation HO clutch) slipped like mad at 762 lb-ft torque in 5th and 6th gears - with no trailer hooked up. The solution was a South Bend Con OFE.

 

[betterthanstock]

The DMF will make a somewhat noticeable popping noise when you've reached the limits of the springs, and you're essentially beating the rivets to death. It's permanent deformation, and also occurs at speeds below 500 rpm (for 06 and up trucks - 05. 5 had a fuel cutoff at 475). When the rivets break, you're dead in the water with a 2 piece DMF - 2 separate pieces

So how about



1--stronger springs by 30%



(this will actually raise the danger speed though to about 1. 3x475=617 rpm)

:{

So maybe only 10-20% stronger?



The only time you run into trouble is when you lug the engine in gear at idle.

Or VARIABLE rate springs?



2--rubber bump stops at the end of springs



That's better for the transmission than going to a solid flywheel.



See I'm giving you free engineering advice.

 

[hasselbach]

So how about



1--stronger springs by 30%



(this will actually raise the danger speed though to about 1. 3x475=617 rpm)

:{

So maybe only 10-20% stronger?



The only time you run into trouble is when you lug the engine in gear at idle.

Or VARIABLE rate springs?



2--rubber bump stops at the end of springs



That's better for the transmission than going to a solid flywheel.



See I'm giving you free engineering advice.

You forgot #3...



'Get an Automatic'

 

[blacksheep4x4]

Has there been any news on how this clutch is working out? I thought somebody said there would be an article in the next TDR issue, but can't find anything in it about the South Bend Clutch on the G-56.

 

[Hercules130]

yeah wtf. i was trolling the D-MAX sites, they have multiple choices to replace the DMF'S.