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stock 08 red w/67k....started knocking. drained oil, cut filter...no metal. I haven't dropped the pan yet, but figured id fine some glitter or chunks at least. unplugged the injectors one by one while running and knock didn't go away. pulled started and checked convertor bolts and flex plate looked to be ok....any ideas??
 

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TrailblazerSS
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How is the oil pressure? Mine never made a noise but oil pressure dropped to single digits and trashed the bearings.
 

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TrailblazerSS
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stock 08 red w/67k....started knocking. drained oil, cut filter...no metal. I haven't dropped the pan yet, but figured id fine some glitter or chunks at least. unplugged the injectors one by one while running and knock didn't go away. pulled started and checked convertor bolts and flex plate looked to be ok....any ideas??
If this is AWD there notorious for oil cavitation issues because of the design of the oil pan for the front Diff setup and the pickup tube location , so its possible you could have spun a rod bearing which is what Happen to my 08 3S had to pull the engine so I opted to go with a rotating assembly less the crank from tick performance out NC Bored it 0.10 but I went with GM performance crank from summit. I also install the oil pick tube relocation kit from PCM of NC which comes with rivets but I had mine welded by local weld shop. I'm an ASE Cert Diesel Tech so I was able to save on labor but still had about $4000.00 in parts but its almost bullet proof now and I beat it on everyday. Love driving that thing its like Christmas Morning when you were a kid everyday PS droping the oil pan on AWD is a Pain but it can be down in you driveway just take a lot of patience .
 

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Punch it!
2008 AWD TBSS
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Sorry Man, been there.
GL making it faster
💪
 

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06' TBSS LT2
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577 Posts
Post up a video. Make sure its ice cold (engine).

Then after it gets to operating temp raise the rpms up to about 2500 and hold.
Drive it a bit and do it again while hot.

If it quiets down?

You have piston slap my friend.

What happens is over time it'll get a little noisier. But it is inherent in the piston skirt design of LS engine.

It's not harmful. Just an annoyance.

If you cut the filter and see nothing in there or the oil? It's either a lifter or piston slap. I'm guessing piston slap as almost every tbss ever made has some.

Some things that cause it to get louder are someone revving it out or beating it up a bit while it's still pretty. Old (oil not warmed up yet - don't go by coolant temps) and it'll beat up the Teflon coating on the skirt.

Watch some videos on YouTube

"LS2 piston slap".


Want to hear a really bad case of it?


Looking forward to your research and investigation.
 

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TrailblazerSS
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My LS2 with 5000 miles toasted the rod and main bearings. I am AWD with the PCM kit. The previous owner had the Melling 10296 oil pump on the motor. I am using the 10295 on the 408 as I question if the high volume pump could have been pumping the pan dry.
 

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If this is AWD there notorious for oil cavitation issues because of the design of the oil pan for the front Diff setup and the pickup tube location , so its possible you could have spun a rod bearing which is what Happen to my 08 3S had to pull the engine so I opted to go with a rotating assembly less the crank from tick performance out NC Bored it 0.10 but I went with GM performance crank from summit. I also install the oil pick tube relocation kit from PCM of NC which comes with rivets but I had mine welded by local weld shop. I'm an ASE Cert Diesel Tech so I was able to save on labor but still had about $4000.00 in parts but its almost bullet proof now and I beat it on everyday. Love driving that thing its like Christmas Morning when you were a kid everyday PS droping the oil pan on AWD is a Pain but it can be down in you driveway just take a lot of patience .
Ummmm.... AWD has nothing to do with it, they use the same oil pan and pickup.
 
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