LBZ loud knock undiagnosed - Page 2 - Chevy and GMC Duramax Diesel Forum
06-07 LBZ & LLY Duramax Powertrain Discussion of components that are directly involved in the power production and all that is needed to get and keep the truck moving . Engine , Transmission, Etc.

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post #11 of 20 (permalink) Old 09-02-2019, 12:10 PM
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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!

2006 LBZ 2500 CCSB 2WD
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post #12 of 20 (permalink) Old 09-02-2019, 03:11 PM Thread Starter
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Originally Posted by BAMAWHISTLER View Post
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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06 lbz; No zone trans with ppe triple; delipped cut coated lb7 pistons, lbz rods;Keyed crank and cam, oil pump; Arp main studs, head bolts, rod bolts, flex plate bolts; air dog 165; stock cp3 with new fpr, 30 overs; PPE Mani and ups
profab y bridge and coldside; banks hotside; dk heads; half of my 401k...
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post #13 of 20 (permalink) Old 09-02-2019, 03:24 PM
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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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post #14 of 20 (permalink) Old 09-05-2019, 08:12 AM
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Ever find out what the noise is?

2006 Silverado 2500HD Duramax
8th VIN number is 2
ZF6 Transmission
Bilstein 5100 Shocks
285/75/16 BFG KO2's
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post #15 of 20 (permalink) Old 09-05-2019, 05:13 PM
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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.

07 LBZ SLT 4X4 CrewCab/SB
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post #16 of 20 (permalink) Old 09-05-2019, 07:14 PM Thread Starter
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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.
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.

06 lbz; No zone trans with ppe triple; delipped cut coated lb7 pistons, lbz rods;Keyed crank and cam, oil pump; Arp main studs, head bolts, rod bolts, flex plate bolts; air dog 165; stock cp3 with new fpr, 30 overs; PPE Mani and ups
profab y bridge and coldside; banks hotside; dk heads; half of my 401k...
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post #17 of 20 (permalink) Old 09-05-2019, 07:27 PM
 
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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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post #18 of 20 (permalink) Old 09-05-2019, 07:39 PM
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My condolences on your problems, but this doesn't look like a cheap and easy fix.
Pushrods.... are pretty cheap.
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post #19 of 20 (permalink) Old 09-05-2019, 08:38 PM Thread Starter
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Quote:
Originally Posted by Diesel gnubie View Post
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.

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

06 lbz; No zone trans with ppe triple; delipped cut coated lb7 pistons, lbz rods;Keyed crank and cam, oil pump; Arp main studs, head bolts, rod bolts, flex plate bolts; air dog 165; stock cp3 with new fpr, 30 overs; PPE Mani and ups
profab y bridge and coldside; banks hotside; dk heads; half of my 401k...
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post #20 of 20 (permalink) Old 10-22-2019, 07:09 PM Thread Starter
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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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06 lbz; No zone trans with ppe triple; delipped cut coated lb7 pistons, lbz rods;Keyed crank and cam, oil pump; Arp main studs, head bolts, rod bolts, flex plate bolts; air dog 165; stock cp3 with new fpr, 30 overs; PPE Mani and ups
profab y bridge and coldside; banks hotside; dk heads; half of my 401k...
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