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Discussion Starter #1
Finally took delivery from a private party on my new to me 06 lbz. I have had a lot of duramaxes over the years and a few lbz's and have really enjoyed them. I was so excited to pick up this truck as my old man tow pig as I planned on keeping forever. The truck came from a diesel mechanic who seems very reputable, and who I am still giving the benefit of the doubt too.

Truck was delivered 5 hours across Montana to me this morning. I paid and drove the truck for a bit and it seemed very solid all around, after 5 minutes I came home and noticed kind of a loud thumping sound. I turned it off and looked through everything and tightened everything and seemed to go away on next startup. Took a drive after a while with the wife and 5 minutes in I shut it down and put on a tow truck after checking everything as it sounds like its coming apart. Beyond bummed obviously. Anyone have any ideas? Currently at my trusted shop till next week when they can get to it I hope.

 

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Discussion Starter #3
Sounds like it could be an exhaust leak.
I sure hope something simple, but couldn't feel anything at the time. Of course we were diagnosing in a busy parking lot as well. Thanks for helping my hopes.
 

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Hopefully its something not to serious. Being that it's in rythem with the motor and has a deeper sound, I would guess exhaust. Next guess would be valve train, but usually that is quicker due to being cam controlled.
 

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Looks like a nice truck, did you contact the seller? Might be able to provide some clues. Check the usual stuff like removing the oil fill cap while it"s running to check for crankcase blowby. Any exhaust smoke while it's running?
 

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Discussion Starter #6
PHP:
Looks like a nice truck, did you contact the seller? Might be able to provide some clues. Check the usual stuff like removing the oil fill cap while it"s running to check for crankcase blowby. Any exhaust smoke while it's running?
I was really excited for the truck, hopefully my next thread is just about the truck lol.

Seller was really surprised as again they had zero issues on the drive down, nor did I after my initial drive until I heard the noise and went away.

No cel, no blowby whatsoever, no exhaust smoke or hazing and seems to run clean. I may go poke around it today and see if the sound is there on a cold start as well. I am trying to round up new fuel filters to put on but not sure where else to look.
 

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?
Any change in oil pressure?
Any codes? (no CEL, but there could be codes)
Rod knock is louder.
Injector knock usually isn't that loud, but I've never heard failing 60 overs.
In between.

Phone picks up everything, can you isolate? Front rear left right upper lower...
Manifold leak either is or isn't, doesn't come & go.
 

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Discussion Starter #8
?
Any change in oil pressure?
Any codes? (no CEL, but there could be codes)
Rod knock is louder.
Injector knock usually isn't that loud, but I've never heard failing 60 overs.
In between.

Phone picks up everything, can you isolate? Front rear left right upper lower...
Manifold leak either is or isn't, doesn't come & go.
Oil pressure holds steady as it should. Started again this morning and same sound so shut it off immediately. I don't have a code scanner unfortunately available, may borrow one and go check this afternoon however.

To me it seems to be coming from the front passenger side, I can't seem to isolate well as the sound is loud and echoes through the engine bay. I can seem to feel it pulsing with the knock in the cold side boot slightly and the intake slightly it seems.

Hurry up and wait kind of situation, hopefully my mechanic can get to it this week but he has been really busy lately. I checked everything again this morning and don't see anything loose etc anywhere, no leaks.

Appreciate all ideas, I figure worst case once it gets solved I can add solution and it can be search material if others encounter a similar issue.
 

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Nice lookin truck from the pic. How many miles on the truck, and how many on the engine? Any warranty left on the build?
 

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Nice lookin truck from the pic. How many miles on the truck, and how many on the engine? Any warranty left on the build?
Truck has 155k, 8k on motor build and transmission build. No warranty unfortunately as previous owner who is a diesel mechanic built it himself.
 

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Hope you got a good enough deal on it to be able to justify a rebuild if necessary. If not, new trucks are for sale every day of the week. That being said. I doubt I'd ever be able to buy a new one. Rather deal with the current LBZ pig!
 

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Hope you got a good enough deal on it to be able to justify a rebuild if necessary. If not, new trucks are for sale every day of the week. That being said. I doubt I'd ever be able to buy a new one. Rather deal with the current LBZ pig!
Im already in love with the truck so worst case I will invest in a rebuild I think. The paint is new and it has a lot of goodies etc. I will eventually get it to stock height with some smaller tires as I am getting old.

Expecting the worst while hoping for the best. All relative on what happens on how good of a deal I have, I thought I did good but my mechanic will tell.
 

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Sounds like a broken exhaust pushrod, and the exhaust pressure is coming back up through the intake and out the air filter which is why its so loud.

Pull the injector plugs one by one, and it should quiet way down once you find the right cylinder.

Then pull the valve cover and look for broken parts. If it is the exhaust pushrod, replace all 8.
 

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Put a stethoscope on each cylinder, that will isolate where the noise is coming from. If you don't have one, get a cheap one from Harbor Freight or use a yard stick or dowel rod. Metal is better than wood for transmitting noise. Can't really hear a knock in your video, sounds more like a miss. Start out simple, then progress from there. Once you have isolated the area of the noise, pull the connector for that particular injector. If the noise goes away, you have isolated the cylinder. Could be something as simple as an injector. I have had one act up intermittently for a period of time, then gradually go into a knock. Also had an injector start knocking so loud, you would think it had thrown a rod. Something else that will create a knock is a clogged fuel filter but you would notice a power drop with the motor most likely into limp mode.
 

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Discussion Starter #16
Put a stethoscope on each cylinder, that will isolate where the noise is coming from. If you don't have one, get a cheap one from Harbor Freight or use a yard stick or dowel rod. Metal is better than wood for transmitting noise. Can't really hear a knock in your video, sounds more like a miss. Start out simple, then progress from there. Once you have isolated the area of the noise, pull the connector for that particular injector. If the noise goes away, you have isolated the cylinder. Could be something as simple as an injector. I have had one act up intermittently for a period of time, then gradually go into a knock. Also had an injector start knocking so loud, you would think it had thrown a rod. Something else that will create a knock is a clogged fuel filter but you would notice a power drop with the motor most likely into limp mode.
I bought new filters etc, but after having it towed to my mechanic he has it in the back of his lot without a lot of access, and I respect him enough to not poke around and try troubleshooting in his lot. Honestly I don't have the work area to remove the lift and get it back to stock which my mechanic was going to do anyways for me as well.

I trust my mechanic as he has done incredible work for me for years and is very honest and reasonable with prices. Unfortunately he is very busy because he is a good honest diesel mechanic here, so I am in a be patient mode.

I do wish I did more troubleshooting, but at this point had it in a parking lot away from home and decided to just get it to my mechanic.
 

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History ?

Truck has 155k, 8k on motor build and transmission build. No warranty unfortunately as previous owner who is a diesel mechanic built it himself.
I too own a 2006 LBZ Crew, 4x4, shortbed, and even though I have more than 200,000 miles on mine, I have never seen the numerous issues you have. Do you know the history of your vehicle ?

I have replaced both half-shafts, both front hubs, the tranny cooler and power steering hoses, and at just under 200K, the front brakes although I could have waited (I got anxious).

Your truck has an engine and tranny rebuild (complete or partial ?), and a paintjob at less than 150,000 miles.

The skeptic in me thinks that you are no less than the 3rd owner, and that at least one of the previous owners did not treat this truck kindly. It appears likely that a previous owner had or anticipated mechanical problems and passed the truck (at a bargain) to the diesel mechanic who did the rebuilding, and if he intended to keep the truck, he changed his mind and flipped it to you.

I don't know if CARFAX would show all of the story, but I would have investigated as much as possible. I look for the ownership periods, particularly how many there have been, how long the 2nd owner back held the title, when the mechanic got the title compared to your purchase, service records, etc.

My condolences on your problems, but this doesn't look like a cheap and easy fix.
 

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Discussion Starter #19
I too own a 2006 LBZ Crew, 4x4, shortbed, and even though I have more than 200,000 miles on mine, I have never seen the numerous issues you have. Do you know the history of your vehicle ?

I have replaced both half-shafts, both front hubs, the tranny cooler and power steering hoses, and at just under 200K, the front brakes although I could have waited (I got anxious).

Your truck has an engine and tranny rebuild (complete or partial ?), and a paintjob at less than 150,000 miles.

The skeptic in me thinks that you are no less than the 3rd owner, and that at least one of the previous owners did not treat this truck kindly. It appears likely that a previous owner had or anticipated mechanical problems and passed the truck (at a bargain) to the diesel mechanic who did the rebuilding, and if he intended to keep the truck, he changed his mind and flipped it to you.

I don't know if CARFAX would show all of the story, but I would have investigated as much as possible. I look for the ownership periods, particularly how many there have been, how long the 2nd owner back held the title, when the mechanic got the title compared to your purchase, service records, etc.

My condolences on your problems, but this doesn't look like a cheap and easy fix.
Carfax is clean, I am indeed 3rd owner. 2nd owner bought in 2012 and started building from there, until he lost a piston due to cracking he stated. He pulled engine and at same time decided to have trans upgraded as well. Long story short but while drivetrain was out it was towed incorrectly and this caused the hood to fly up and cause damage, which was insured by tow company and repaired and repainted at their expense. I do have a fair amount of service records, but some have been tough for previous owner to acquire, namely dmitri's receipt for the rebuild, even though we have both asked numerous times.

Regardless, I took it upon myself to research the owner and the truck a bit before purchase, and took his word on the truck buying sight unseen. Hopefully I was not taken, but I still have a hopeful good feeling about the truck. I am still in contact with the seller who is providing me further receipts as he finds and retrieves them, and again seems like a good person.

Its a bummer buying a new truck that took a month to negotiate, and not being able to even enjoy it for 5 minutes without worry, but I can't imagine the seller would deliver 5 hours if he was worried the truck had issues.

Buying used is always a gamble, this truck was worth it to me for the extras I can see, the paint, low miles, and overall build. Again I am hopeful, prepared for the worst but hopeful for the best. Just wanted a cool reliable camper puller. 'dunno;

...I should have just engaged in a full mid life crisis and bought the new mid engine vet lol
 

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Discussion Starter #20
Well, after many weeks waiting my mechanic finally has the truck in the shop. After pulling everything cylinder 3 had a stuck exhaust valve, cylinder 4 also has a miss as well and has accumulated a fair amount of rust comparatively. :( Bummed as obviously this is getting to worst case scenario, but as they say "aint that a kick in the head."

My mechanic wasn't impressed with torque specs so they are going through everything as well to make sure all is good. Adding a new water pump while I am there, and I believe a garrett powermax turbo while everything is off.
 

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