C 15 engine noise

Silly question, has anyone ever flushed the power steering system and changed the filter in the reservoir?. Power steering pump starving for oil. Will cause cavitation and a whinning noise at higher rpm's.

 

<edit/disregard> apparently jason is replying to your thread

 

What model truck is it? A friend of mine has a 2002 379 and he had some kind of noise that several people looked for and couldnt find. Ended up being the cab mounts were shot. I have no idea if its the same for yours but it could be something to check.

 

Another thought, how many mi on trk?. Have you checked vibration damper on crank?. They do go bad and will cause torsional vibrations in the crank, if bad enough the vibrations can cause crank failure. Especially under a load.

 

I've always replaced them at about 500k. Only way i know is to take it off and put on a known good one. My no means do you want to run that engine with out the vibration damper. The harmonics from the firing of the cyl's will desroy the bearings or the crank in short order.
Have you checked the isolator bushings and rubber exhaust part hangers. If the rubber is torn and the exhaust parts are rubbing metal to metal will set up a vibration through out the chassis. With out being there personally i'm just guessing. Hope it helps