BIGROD

I have a bad vibration in the motor between 1200 and 1500 rpm. If you let off the accelerator it gets better. But the vibration seems to get worse after the motor warms up. It can be felt at a idle then. It also does this setting still if you raise the idle up. I have noticed that the tac has started showing the truck idling at 300 rpm and when driving will change the rpm running a steady speed. When listening to it idle the truck is not missing.
Does anyone know what's wrong with this truck. It's a 2006 6 speed bone stock no mods of any kind.
Thanks for any help you can give.

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deere country

I would bet your dual mass flywheel is on its way out. Their isn't much to cause a bad vibration in your engine if you are sure it's not engine related like an engine miss or harmonic balancer.

I don't beleive their is any way to look at your flywheel without pulling the trans.

BIGROD

Where is the harmonic balancer at on these motors?
I took the truck to a transmission shop that the owner is very honest. After he drove it with me in there he said that he didn't think that there was anything wrong with the clutch. He also said that if it was a flywheel problem that would be the first that he seen do that.
I'm should have time tomorrow to start checking small things.
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deere country

Harmonic balancer is bolted to the front of the crankshaft and also drives the serpentine belt. Their is always a first time for everyone, does his shop work on diesel trucks that use the dual mass flywheel?

BIGROD

Yes his shop does work on them he was even replacing one the day I was there. I ask what cluch he used when replacing them, he said they use Luke clutch that they are made in the USA and he hasn't had any problems from them. I have never heard of Luke clutches.
He said he thought it could be the harmonic balancer. I thought they were internal not on the front of the motor. Is there away to check the harmonic balancer?
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madhat

It's not really a harmonic balancer, it's an external dampener. (no big deal, just telling you the dodge nomenclature) It is on the front of the motor at the crank.

The only way to check is to inspect it, the service manual says to inspect it for the rubber missing or worn. I assume there is some way you could hook it up to a balancing machine, but I don't know what or who would have something like that.

If, by chance, you need to replace it, the new 6.7 dampener is the upgrade, I believe. You'll need a few new bolts and a new fan pulley. It's not terribly hard to do, I did it in about three hours. Most aggravating thing was getting the fan shroud out.

deere country

The balancer or dampener very rarely have issues. About the only time I have seen them fail is after being oil soaked for to long, from a leaking oil seal or gasket or extreme old age.

I have yet to see a 1st gen truck fail from old age but have seen many 24 valves fail from oil contamination. Pretty easy to look at it and make an assessment with a visual. I have seen more dual mass flywheel failure than I have ever seen dampener failure.

BIGROD

I finally got time to look at it today. The vibration gets worse when it's warmed up. I stated toe truck everything is fine when you first start it runs smooth except it shakes really bad idling. Raise the idle it smooths out and sounds perfect with not shake. After letting it run for about 20 minutes it shakes worse at idle and the shake stas in it to about 1100rpms. I noticed it sounds like a lifter raddle in the motor then.
Could I have valves that need to be adjusted? You can't hear the lifter raddle unless the hood is up and the motor is warm. Cold there is no raddle.
I was thinking that if the balancer was bad I would be able to see a shake in it like on the old gas motors, all that looked fine it only shook with the motor.

deere country

After your last post I would start with the flywheel. I beleive what you are hearing is traveling threw the crankshaft and given you a false sense of where it's coming from. I don't have any other advise. I know it's likely not what you wanted to hear but my experience would take me to the flywheel.

You can certainly look elsewhere but that's my best estimation. I have never had valves out of adjustment make a vibration in the motor. That's all I have for you.

BIGROD

Deere country and madhat thanks for all the information. I do appreciate your time that you took answer questions for me.
The thing that keeps throwing me off is it gets worse when it warms up.
I did pull the valve cover at a glance everything seems fine. With my hands missed up I don't adjust valves. If I knew how and had the tools I sure would try. I have a friend with a man in another town that works on 18 wheelers. I was thinking about trying to have him listen to it and maybe go ahead and adjust the valves.
How bad can a flywheel get before it tears up other things? And do you know anything about Luke clutches andflywheels?
Thanks again for everything

madhat

I'm having a hard time thinking valves are the issue. Anything can happen, but I'm not feeling valves. I could be wrong.

Never heard of a Luke Clutch. I'm not in the market for a clutch, so that could be why as well.

deere country

The luk brand clutch is a good product they have been around since the 70s. I beleive they were the first ones to offer a clutch kit meaning they included all the parts needed for a clutch job, and you didn't have to order individual parts to do the job.

It's likley your dual mass flywheel is the problem not your clutch. They have been around for a long time and in theory work great. The problem lies in their durability and cost. They are generally twice the price or more of a standard flywheel.

It's very rare to every reinstall a dual mass as people usually will opt for the less expensive and old reliable standard flywheel. The problem is multiplied when the factory horsepower is increased.

I would take it to the trans shop you where just at. If they do this type of work they should be able to remove your trans on the hoist in less than an hour and a half. And nearly the same time to reinstall it. Should cost you less than a few hundred dollars.

I have seen on a few occasions where they will let loose and destroy your bellhousing and your trans if they have an integrated bellhousing.

deere country

As to it changing with the warm up temps it's related to the spring loaded dual mass portion of the flywheel. If you take a look at how they work you should have an understanding of why the temp can change their manners.

I like the Sachs or Valair clutches as I beleive they are a better product, but some think the southbend clutch is the only thing to use. I have seen several southbend branded clutches fail prematurely but their are likley more of them out their also.

BIGROD

Thanks
The transmission shop I use puts in the luk clutchs. He said he has never had any problem wit them. I just never heard of them.
I figure it might need the valves adjusted seeing how the injectorswere pulled and tested awhile back and I don't remember the valves being readjusted.
I know that i heard a lot of 18 wheelers use the dmf and a friend told me he has a friend that works on them. So I thought having him look at it might be a good idea. Seeing how money is tight just buying a house and getting back on my feet after a devorice a few years ago. I just want to make sure I only spend money on what I need and nothing extra.
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Jeff in TD

A friend's truck had a noticeable vibration at idle, you could feel it more when the engine is under heavy load at lower or mid rpm.

Turned out it was an injector.