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5th Gen 6.7 HO vibration

Austin

Austin

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St.Louis, MO
I picked up a 2019 3500 tow pig with 67k. It was already deleted and has a 5" straight pipe. When I test drove it the owner had all his stuff in it and the odd vibration from the glovebox/dash was ignored as he shuffled stuff around and it partially went away. Turns out, it wasn't his stuff and now I can't figure out WTF the vibration is. It's only at idle that it happens, either in park or at a stoplight. I've torn the dash apart and every once in awhile I can get my hand on something that makes it slightly less, but it's not the root problem. I know it's a diesel and they make noises, but this is incredibly annoying and loud in the cab with the doors closed.

Here is a video, it kinda picks up the vibration.



This was deleted when I bought it, looks like a GDP kit by the branding. I know nothing about delete kits. You can see in the later portion of the video that the coolant riser/return/expansion tank like etc vibrate pretty good. The video doesn't actually capture how fast it's vibrating, but seems to be in tune with the vibration in the cab. The delete kit bracket seems flimsy. My 2018 6.7 was stock and I don't recall if they vibrated that bad. Should that be vibrating that much and where else should I look?

Other thoughts ....
  • the exhaust is not rubbing
  • the vband screws are not hitting anything
  • nothing inside the dash seems to vibrate (but thats where the sound is)
  • The big box at about the 10sec mark does seem to stop the vibration to some extent, not sure what that is ... the numbers on the stickers pull up no parts.
  • the vibration happens with & without the climate control on
 
Time for new dumbbells

IMG_4672.jpeg
 
That engines seems to vibrate more than my '12 did...I seems like something it touching the cab maybe from the engine compartment?
 
akguy09 said:
That engines seems to vibrate more than my '12 did...I seems like something it touching the cab maybe from the engine compartment?
Click to expand...
This,

positive nothing from exhaust/engine touching cab/trans etc? Sure sounds like that. Someone has been in there to mess with the exhaust etc in that area.....
 
There is a hanger near the bell housing/trans mount (cant remember which) that was for the trash cans and it gets super close to aftermarket exhaust, the factory stuff necks down at the hanger where it goes into the SCR/DPF.

On my 19 and 21 I removed the hanger from the frame when i stabbed in the straight pipe.


It is insane how quiet the 5th gens are "Straight piped" vs what a 2nd gen sounds like. Most people that aren't in the know think the truck is stock.
 
75RamRunner said:
It is insane how quiet the 5th gens are "Straight piped" vs what a 2nd gen sounds like. Most people that aren't in the know think the truck is stock.
Click to expand...
I’m deaf so I may be wrong but I read that 6.7s can somewhat sound like a typical pre-CR diesels after a tune.

The quietness of a diesel engine is largely achieved by multi-event fuel injection. Whenever a tune which change that to single injection will produce the ‘diesel knock’ loud noise.

Austin I think you should have whatever tuner you have on it checked or try a different tuner to try fix that vibration at idle. I reckons vibrations are transmitted into cab via HVAC stuff and producing the noise you want to get rid of.
 
TrailTamer said:
I’m deaf so I may be wrong but I read that 6.7s can somewhat sound like a typical pre-CR diesels after a tune.

The quietness of a diesel engine is largely achieved by multi-event fuel injection. Whenever a tune which change that to single injection will produce the ‘diesel knock’ loud noise.

Austin I think you should have whatever tuner you have on it checked or try a different tuner to try fix that vibration at idle. I reckons vibrations are transmitted into cab via HVAC stuff and producing the noise you want to get rid of.
Click to expand...
I ran a single event tune on my 12' for a short while.
It wasn't hardly any louder in cab, and def no vibes.
Only ever had a vibration like that when sorting out the downpipe hanger/trans mount area.
 
akguy09 said:
That engines seems to vibrate more than my '12 did...I seems like something it touching the cab maybe from the engine compartment?
Click to expand...
The engine doesn’t really vibrate, you put your hand on the motor/frame/body and you don’t feel a thing. It’s smoother than my 2018 non-HO. It’s just that coolant riser that seems to vibrate. I think the frames per second on my iPhone make it look worse than it is. Obviously it's still vibrating, but it's not that slow rocking that the video make it look like.

75RamRunner said:
There is a hanger near the bell housing/trans mount (cant remember which) that was for the trash cans and it gets super close to aftermarket exhaust, the factory stuff necks down at the hanger where it goes into the SCR/DPF.

On my 19 and 21 I removed the hanger from the frame when i stabbed in the straight pipe.


It is insane how quiet the 5th gens are "Straight piped" vs what a 2nd gen sounds like. Most people that aren't in the know think the truck is stock.
Click to expand...
I've read that the really long vband bolt can hit the frame or trans lines, I've throughly inspected the downpipe and nothing is rubbing. Only spot I can't see/feel is about 6 sq in where there is heat shield on the other side, but the heat shield looks firmly attached to the body so I don't suspect that.

The straight pipe was quite in the cab, but not quiet enough for school pickup lines :laughing:. The sound bouncing off the brick walls gets the LEOs there attention so I put the massive Donaldson M100463 Muffler on it, much quieter outside and no loss of power. I have to focus on hearing the exhaust when at the front of the truck otherwise I wouldn't hear it.

TrailTamer said:
Austin I think you should have whatever tuner you have on it checked or try a different tuner to try fix that vibration at idle. I reckons vibrations are transmitted into cab via HVAC stuff and producing the noise you want to get rid of.
Click to expand...
No tuner came with it but I suspect your right about he vibrations carrying into the cab via hvac. I would like to get a tuner/dial/whatever that has fuel economy and towing modes. I know nothing about them tho.

That bracket from the delete kit that supports the coolant piping is thin, flimsy and not attached that sturdy, not sure if thats by design.
IMG_9108.jpeg



I'll put the dashboard back together tonight and try stiffening that bracket to test.
 
Last edited:
Austin said:
I'll put the dashboard back together tonight and try stiffening that bracket to test.
Click to expand...
I have an idea to try narrow down on where it’s coming from. Do you have someone to help you, by to hold on heater core hoses and/or A/C lines under the hood to dampen the vibration with their hands while you sit inside to listen for any change in noise note/level?
 
TrailTamer said:
I have an idea to try narrow down on where it’s coming from. Do you have someone to help you, by to hold on heater core hoses and/or A/C lines under the hood to dampen the vibration with their hands while you sit inside to listen for any change in noise note/level?
Click to expand...
I did that with the wife in the cab, the thing that helped most was simply pinching the overflow tank hose closed :confused:


Before I left for lunch I pulled the two bolts that support the hoses.


Not a single noise in the cab. :smokin: (lots of wind noise outside)

As stiff as the multiple hoses are it seems to stay in place pretty well. I did notice that exhaust gas pressure hose was barely tightened, so I snugged that up. Drove about 4mi on it and it's like a new truck ... love it.

Now I need to figure out if can actually leave it like this. Got the idea from Youtube videos putting delete kits on. Some have much nicer brackets, some don't have any at all. This one is garbage, I don't know how long it's been on but it already fairly bent. I don't doubt they were originally attached to something, but not sure attaching them directly to the block like that is the best idea
 
Cheapo HF mechanic stethoscope and 5min of poking around and you'll have a lot better idea of where the problem is....
 
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