I figured I would start here as this crew is pulling heavy loads and most issues are going to arise when pulling and be hidden when not pulling.

Which is my case. 

The past few trips into our local forest I have experienced a shrill shrieking noise under the hood of our 05 F350 PSD 6.0 dually.

Let me set the stage:

The ride into the local forest is slow and very hilly with lots of turns takes about 15 - 20 minutes to get to our trail head on all paved but bumpy roads.

Our new noise is only present during the point of throttle and torque at these low speeds.  If I flutter the gas pedal without adding additional torque I can encourage the shriek to maintain until the torque of the truck catches up.

I have taken this to the dealer yet they cannot duplicate it.

I have been able to duplicate it not under tow by getting on the truck (0 to 60 stuff) following I was also able to duplicate it in my driveway while in park.

I have read that the tension bearing is an issue in these trucks.  The noise certainly sounds like a dry bearing.

Any thoughts?  Thanks in advance.

Jim

The first time I took it in for this the dealer found the water pump leaking and a gasket on the y pipe whistling.  They replaced the belt, pump and gasket.  Sent me on my way and the problem is still persistent.

I am going to hate to get caught on the side of the road with the family in the cab and in the trailer.

Does the noise vary by engine speed? It sounds as if it might be serpentine belt related. If it's not the belt itself, if could be any bearing being turned by the belt. This would include the belt tensioner pulley bearing, the alternator bearing, water pump, power steering, air conditioner compressor etc. A mechanic using a mechanic's stethoscope should be able to pin point the source of the sound very quickly.

Gard

t is my experience on any engine, that if a bearing is dry or shot it will make a noise all the time 9although it might be softer at lower speeds and loads) This sounds like a simple undertensioned belt. The fact that it does it under lower speed conditions it tells me that it is either the alternator belt or the power steering belt.

Try turning the steering wheele to full lock (with the engine ideling) - then try to turn it some more. If it squeels, then you have a loose power steering belt. If not I would check the Alternator belt....this is more than lightly the case - as when the viscous fan engages (in the twistie and turnie areas) it demands more torque from the belt and this could cause the squeel....

Good luck

Check the hoses and clamps between the turbo, aftercooler and the intake... You may be hearing turbo boost air leaking.... hose may have oil on the inside and is beginning to slip off of fitting... You won't hear it unless the charger is making boost pressure.

The noise is just before torque kicks in, the in between between accelerating and not and most prominent at a low crawl.

A better example of the torque position:  "When you have a loose chain on a motorcycle or regular bike.  The chain is slack with no torque but just as it tightens up but not tight all the way."  That is the position of throttle I can get into and once I get the noise I can accentuate it by fluttering the gas for a few minutes ensuring I do not add extra torque.  Speed could be 5 - 15

I am happy with your responses nice to get some opinions.  Thanks