5.3 LS w/4L80 Mystery Noise

[Rustybucket73]

Just finished up budget LS swap on a '73 C10.

Bone stock 5.3 from a suburban
4l80e with a HD2 kit, stock converter

Has a weird noise when ever I rev up to around 2500rpm while parked. Noise also comes back around the same rpm while driving.

Converter is seated all the way in the pump.

Exhaust has v-bands and has some leaks, but I don't think a exhaust leak sounds like that?

Any idea what it could be?

Noise is in the video about 30 seconds in.

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[Honky Kong jr]

Sounds like your flex plate is living up to its name.

 

[Rustybucket73]

I guess I can take that as everything is fine?

 

[Honky Kong jr]

I guess I can take that as everything is fine?

No it sound like it rubbing somewhere. Look in around the flex plate and converter for scrape marks could be a crack in the flexplate too. And welcome to GMSB

 

[Rustybucket73]

Ok, thanks. I'll check it out

 

[74propu]

No it sound like it rubbing somewhere. Look in around the flex plate and converter for scrape marks could be a crack in the flexplate too. And welcome to GMSB

2x flex plate look close between the holes in the flex plate

 

[74 Shortbed]

Flex plate is broke or loose...

 

[Jrgunn5150]

Sounds like the flexplate is rubbing or something.

Did you change to the flat 6.0 flexplate?

 

[Rustybucket73]

Sounds like the flexplate is rubbing or something.

Did you change to the flat 6.0 flexplate?

Yeah, it has the 6.0 flexplate and spacer

 

[Jrgunn5150]

Yeah, it has the 6.0 flexplate and spacer

And longer bolts?

Is it hitting the oil pan? Are there any witness marks anywhere?

I've found my phone to be a really handy tool in shoving weird places and taking photos that I can then review.

 

[Honky Kong jr]

Rent a bore scope and shove it up around the flex plate.

 

[74 Shortbed]

Better yet, buy one for your phone for $15

 

[Honky Kong jr]

Better yet, buy one for your phone for $15

That too

 

[Jrgunn5150]

Or just recklessly stick your phone places like I do lol.

 

[Rustybucket73]

Want to update the thread.

Took the trans off the motor and inspected the flex plate.

No cracks around the crank bolt holes or anywhere else on the flex plate.

Didn't see any rub marks on the inside of the bell housing or on the engine behind the flex plate.

Re-torqued all the crank/flex plate bolts to spec and put everything back together.

Still makes the same noise.

Now I'm thinking its the pump?