07 LBZ Duramax cricket sound

[BowmanFarms]

I just recently purchased a 2007 LBZ 2500 Duramax. Truck is completely stock. It is making a sound similar to a BUNCH of crickets chirping. I need the truck to pull with but I'm afraid to drive it so I don't mess it up. I searched google and the forum and kept coming up with the belt tensioner, but I am certain that it is not because it is coming from the back of the motor. It seems to only do it at an idle and goes away as soon as it gets a few rpms. It doesn't seem to do it until the engine gets to operating temperature. I'm new to Duramax's so any help would be greatly appreciated.

Thanks,
Chris

 

[Hot COCOAL]

If your positive its coming from the back of the engine, then I'd look at all the exhaust piping and connection's... Manifold's, collectors, downpipe connection at the turbo and exhaust ect...

The fact it goes away with a few RPM's makes me think it may be an exhaust leak...