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

[Mingoglia]

I became a TDR member about a year before I bougtht my truck. I was amazed at the amount of information being batted around by mature adults. This was a sharp contrast from all other newsgroups I've participated in. For example, the dieselstop in my opinion is a much younger crowd and tends to have a lot more flaming than the TDR. I am a member on the dieselstop just because I enjoy diesel trucks of all makes, although I typically just add my $02 in the Towing sections.



I don't know if it's because the 3rd gen trucks appeal more to the younger, more immature crowd more than past trucks, or what but I'm starting to be ashamed of the TDR badge I have in my grill. Yeah, I'm only 29 so I'm considered one of the young ones, but the entire tone of this newsgroup is changing for the worst... . it's very sad to say this. The TDR may go down in history as just another childish newsgroup where a group of adults can't have a mature conversation and express ideas without someone flaming them.



Peter is a stand up guy and I believe Tim is doing a great thing for other owners once the time comes to upgrade/replace their clutch. Of course Tim is getting a heck of a deal out of it, but don't give the guy a hard time and start yet another flame war about the G56.



Mike

 

[HeavyHauler]

Nice post Mike - I whole-heartedly agree. The 3rd Gen forum is definitely the worst for this type of content.

 

[Gary - K7GLD]

Nice post Mike - I whole-heartedly agree. The 3rd Gen forum is definitely the worst for this type of content.

That's not the fault of the 3rd genners themselves - it comes mostly from outsiders, working on heresay and rumors. Some concerns may well be valid - and to some degree, sensitivity of 3rd gen owners is understandable.



Hell, us 24 valve guys take this sort of stuff all the time with LP and VP-44 issues - and have to grin and bear it. Hopefully, the G-56 will NOT be the 3rd gen equivelent to the VP-44 - but some potential buyers ARE gunshy, and want concerns and questions answered - meanwhile, the 3rd genners need a bit more tolerance and understanding for the concerns of outsiders.



I *know* that my VP-44 equipped '02 has been totally reliable and trouble-free to date - and freely tell others of my experience - but I'm also very aware of the track record of these trucks, but hardly feel compelled to react with anger just because someone attacks trucks like mine and more specifically, the VP-44 - it comes with the territory!

 

[hasselbach]

Actually, I think its great that TIM is offering to sacrific his brand new truck in the interest of science. I just think the DC engineering group is a pretty smart bunch of people, who are tasked with making something strong but cheap. I wouldn't be surprised that you see problems develop with the g56 with the elimination of the shock absorbing benefits of the DMF. Your driveline is only as strong as the weakest link, and removing the DMF will be very interesting project. I'm sure DC evaluated the g56 without the DMF and found that the costs to upgrade the g56 without a DMF was greater than the cost of the DMF and a stock g56. Afterall, isn't the g56 rated for something like mid 400's for torque?



Time will tell.

 

[scotty1]

I became a TDR member about a year before I bougtht my truck. I was amazed at the amount of information being batted around by mature adults. This was a sharp contrast from all other newsgroups I've participated in. For example, the dieselstop in my opinion is a much younger crowd and tends to have a lot more flaming than the TDR. I am a member on the dieselstop just because I enjoy diesel trucks of all makes, although I typically just add my $02 in the Towing sections.



I don't know if it's because the 3rd gen trucks appeal more to the younger, more immature crowd more than past trucks, or what but I'm starting to be ashamed of the TDR badge I have in my grill. Yeah, I'm only 29 so I'm considered one of the young ones, but the entire tone of this newsgroup is changing for the worst... . it's very sad to say this. The TDR may go down in history as just another childish newsgroup where a group of adults can't have a mature conversation and express ideas without someone flaming them.



Peter is a stand up guy and I believe Tim is doing a great thing for other owners once the time comes to upgrade/replace their clutch. Of course Tim is getting a heck of a deal out of it, but don't give the guy a hard time and start yet another flame war about the G56.



Mike

Well put. I think its time to step away from this crap on this and other sites.

When I look around I see very little from the vendors that have been in this industry for a long time now. The sharing of knowledge was once a given. Why bother when you are going to get critiqued? Peter has done far more then most of you would ever appreciate or understand.





Scotty

 

[Mingoglia]

Thx guys... appreciate it...

 

[Tim]

How do you know? I think that it would be a BIGGER service to us G56 owners for you to go and pull 40,000 pounds with a stock G56 and see if it holds up vs. bailing on the stock clutch and flywheel right out of the chute. I'd like to know if it can handle it. If it does, then the DMF debate can get cooled a little. This just adds fuel to the fire.

There is no point in having a DMF if it won't slip at twice the rated load. The entire idea is that it slips to protect the transmission. If it doesn't slip at 40,000 lbs of load, it will never be able to do its job.



I'm doing this for all of us, not just for me. Honestly, I hardly drive my truck except to pull my trailer, and I figure those of you who are running motor upgrades will appreciate it.

 

[hasselbach]

There is no point in having a DMF if it won't slip at twice the rated load. The entire idea is that it slips to protect the transmission. If it doesn't slip at 40,000 lbs of load, it will never be able to do its job.



I'm doing this for all of us, not just for me. Honestly, I hardly drive my truck except to pull my trailer, and I figure those of you who are running motor upgrades will appreciate it.

I think somebody needs to tell TIM exactly what a DMF actually does. Maybe I'll try here, so can somebody quote me?



Class DMF 101



A DMF does not SLIP to protect the transmission, rather it is basically two sets of flywheels, with springs between the two to absorb torsional spikes caused by the cylinders under power strokes. Diesels are not like an electric motor that delivers its power in a smooth, linear form, but more of like 6 jolts within 720 degrees of rotation. Low RPM's compound the problem too. A 6 has harder and fewer spikes say compared to a V8, therefore the DMF provides more of a benefit. Benefit to what? Not so much for a smoother operation, but rather benefit to protect the transmission and driveline from the torsional spiking which in effect hammers the moving parts. I think it also allows the manufacture to use, say a more light duty driveline to save costs. Problems in the past units have seen the springs absorbing so much torsional vibrations that the springs are hammered, and typically self destroy. In concept, its a great idea, but getting one to live is another thing all together.



End of Class

 

[Scrappy]

I think somebody needs to tell TIM exactly what a DMF actually does. Maybe I'll try here, so can somebody quote me?



Class DMF 101



A DMF does not SLIP to protect the transmission, rather it is basically two sets of flywheels, with springs between the two to absorb torsional spikes caused by the cylinders under power strokes. Diesels are not like an electric motor that delivers its power in a smooth, linear form, but more of like 6 jolts within 720 degrees of rotation. Low RPM's compound the problem too. A 6 has harder and fewer spikes say compared to a V8, therefore the DMF provides more of a benefit. Benefit to what? Not so much for a smoother operation, but rather benefit to protect the transmission and driveline from the torsional spiking which in effect hammers the moving parts. I think it also allows the manufacture to use, say a more light duty driveline to save costs. Problems in the past units have seen the springs absorbing so much torsional vibrations that the springs are hammered, and typically self destroy. In concept, its a great idea, but getting one to live is another thing all together.



End of Class

so this DMF is basically the same thing as the sprung center hub in the clutch disk? the clutch disk isn't enough by itself?

 

[hasselbach]

From what I have read, yes, only with greater capacity to absorb vibration. I believe the sprung center hub in the clutch disc is basically there to soften engagement, but that's about it.



Someone correct me if I'm wrong? I'm just passing on what I have read on DMF's and pictures I've seen of them, and when they fail. I don't think they are supposed to actually slip.

 

[JHardwick]

I said this in another G56 thread ... ... .....



We have a DMF because of guys who spend $40,000 on a truck, a diesel truck no less ... ... but want the ride of a comparably priced luxury sedan.



DC already has the heavy towing crowd. Now they want the "I want a heavy duty, diesel powered grocery getter" too!



I'll pay you $40,000, but I want it to ride like a Lexus or I'll cry like a baby!



That's where the DMF came from, and it's gonna be (to quote me from another G56 thread)... ... ... .



Change the flywheel and check the clutch!



I'm not real happy about this at all and will be in the market for a new ride within the next 12 months.



Would I pay SBC to fix a DC problem? ... ... ... . sure, they know their stuff!

Should I have to? ... ... ... . no I don't think so!



I'm just up at arms about it all, I know I'm gonna need a new truck before this one is too high mileaged to get rid of, but the future aint looking bright ... ... ... ... ... .....



On edit ... ... ... . yes, it's like 2 flywheels in one! The smaller flywheel is suspended inside the larger with springs to dampen the spikes (harmonics) of the Cummins. Very weak design for anything other than a grocery getter!

 

[hasselbach]

I said this in another G56 thread ... ... .....



We have a DMF because of guys who spend $40,000 on a truck, a diesel truck no less ... ... but want the ride of a comparably priced luxury sedan.



DC already has the heavy towing crowd. Now they want the "I want a heavy duty, diesel powered grocery getter" too!



I'll pay you $40,000, but I want it to ride like a Lexus or I'll cry like a baby!



That's where the DMF came from, and it's gonna be (to quote me from another G56 thread)... ... ... .



Change the flywheel and check the clutch!



I'm not real happy about this at all and will be in the market for a new ride within the next 12 months.



Would I pay SBC to fix a DC problem? ... ... ... . sure, they know their stuff!

Should I have to? ... ... ... . no I don't think so!



I'm just up at arms about it all, I know I'm gonna need a new truck before this one is too high mileaged to get rid of, but the future aint looking bright ... ... ... ... ... ..... and then there's Tim!

I politely disagree with DC looking to provide a Lexus ride. I think its more of the ability to use as light duty parts as possible, and one way is to use the DMF. I don't recall seeing massive amounts of posts from owners saying the vibration through the drivetrain was bad. But I have read a lot that the DMF is designed to perserve transmissions behind diesels (and those fragile plastic gears in the g56 :-laf )

 

[JHardwick]

I politely disagree with DC looking to provide a Lexus ride. I think its more of the ability to use as light duty parts as possible, and one way is to use the DMF. I don't recall seeing massive amounts of posts from owners saying the vibration through the drivetrain was bad. But I have read a lot that the DMF is designed to perserve transmissions behind diesels (and those fragile plastic gears in the g56 :-laf )

Nope, aint buying it! I've read way more "vibration" problems than "NV5600 failure" problems!



On edit ... ... . okay okay, so DC wants a cheap transmission with a buffer aft the Cummins, and grocery getters want a smooth ride out of a truck!

 

[67guzzler]

You guys rock! This is the best thread ever.



RB1 coming in tomorrow! Woo Hoo!



Plastic Gears -- The wave of the future... . :-laf Got G56? No? You don't know what you're missing. A Brazillian-Made Dual Mass Flywheel Aluminum Gem of a transmission, don't you know... ... with plastic gears AND rated to take up to 400 ft/lbs of torque, thank you.



Now, back to your regularly scheduled (friendly) debate.



Now where did I set that beer????



P. S. I have to agree with hasselback -- If this move to the G56 was done with the intent to improve NVH, then it's a sad failure. The clutch engagement is fantastic -- better than the two NV5600's I test drove when I ordered. But the shifting and drivline on those two NV5600's were far superior. Softer, tigher and way better. As a G56 owner I can only conclude that this was a business decision to go with the G56 and the DMF may be part of the package. MAYBE it's protecting an otherwise inferior transmission?

 

[RJOL]

Tim... I'll be watching this thread to see how it turns out. Thanks for being the test truck...



Peter... Thanks for all you've done to make our CTD's run better. I glad a true professional is looking at this and will let us know the real status of the G56 and what, if anything, is needed to make it better... Good luck...



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Robin

TDR Admin

 

[RJOL]

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Robin

TDR Admin

 

[JHardwick]

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Robin

TDR Admin

 

[67guzzler]

In the spirit of a sense of humor, let's just to re-cap the (G56) humor of it all:



DC decides to make a mid year transmission change with a unit that has a really low launch ratio in 2nd gear (you're shifting to 3rd before you even get a chance to think & this makes the truck slow as crap off the line as compared to the NV5600) and a different final gear ratio that amounts to the buyer getting a 4. 10 ratio even if they don't want it. Gee -- it's great fun getting 16 mpg on the highway on a vehicle that has so much low end grunt that it's a crime to make it turn 2250 rpm at 70 mph. Mind you -- they don't officially tell anyone about this change so if you ordered a truck based on a test drive of the NV5600, you're screwed after waiting 15 weeks for delivery because it was mysteriously held up in a railroad yard because some genius can't count quarts of transmission fluid. Now add to this the fact that after researching this fantastic G56 gem you learn it has a dual mass flywheel which is something that many here (who know way more about it than I do) seem feel that historically it has sucked. Lastly, the icing on the cake is that your 610 ft/lb series 600 engine is driving a transmission that is used on European midrange trucks with engines never outside the 400's in torque.



Does that about cover it? It's really a riot.



Seriously tho -- is telling the truth about the facts of the "introduction" of the G56 by DiamlerChrysler from a buyer's perspective bashing? Why does the truth about these facts raise such a stink?



Someone PM'd me and asked me what I thought of the G56 and should he get a 2005 that had the G56. He said he was a manual transmission guy like me. I said I liked NV5600 and felt that I knew what to expect with it after test driving two of them. I told him I was greatly disappointed that DC made the change with something so materially different from the NV5600 mid year and explained my reasons as obnoxiously enumerated above. But then I told him he should get it if he otherwise liked the truck and he'd be happy over all.



If I had it to do over again, I'd still buy it. It's an awesome truck. But I ain't gonna suger-coat the facts of what happened this spring with the "introduction" of the G56 by DC just to make anyone feel better about their G56 purchase... . That's not honest and doesn't do anyone any good. It is what it is. We just don't know what that "is", is, yet.



Now where is that beer?

 

[hasselbach]

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Robin

TDR Admin

 

[AlexWV]

How do you know? I think that it would be a BIGGER service to us G56 owners for you to go and pull 40,000 pounds with a stock G56 and see if it holds up vs. bailing on the stock clutch and flywheel right out of the chute. I'd like to know if it can handle it. If it does, then the DMF debate can get cooled a little. This just adds fuel to the fire.

Ha ha ha!!! Normally I find myself agreeing with your posts, JGann. But this one is pretty dang funny. If you had an NV5600 and felt like bombing it and also felt like maybe you needed a stronger clutch, you could go to SBC and get you one. That is a nice option I think. Now there will be one for the G56. I seriously do not get this kind of comment. I don't see people ragging on the Edge beta testers or whatever.



So good on Tim to offer up the truck. WTF is the big deal? But since he is already lined up to do that we need somebody else to do all us G56 owners a big service and go out and pull a 40,000 sled. My truck is modified somewhat so it that would probably invalidate the test. That leaves me out.