Screeching F350

First thought - check all the fan belts, they'll squeal like a banshee if overloaded, especially when the radiator fan clutch kicks into full lock. Loose, glazed, rock hard...

Second, pop the belts off and spin all the belt driven accessories by hand, feel for lumpy or sloppy bearings. The alternator, water pump and all idler pulleys should spin freely, the power steering pump will have resistance even at hand-turn speeds but it should be even and smooth turning anyway. They can start going bad and only complain under load at first.

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CAC boots have been a concern on these... the hot side boot at the turbo can become split or porous and make a "reedy" noise. If you have a positive air shut off, some of the early adapter boots were prone to early failures.... I mention this because you speak of high engine loading... which will have boost levels quite high - and, if the VGT vanes are sticky, it isn't hard to get into overboost which can lead to further problems.

Seen the odd tensioner that is getting sticky and can't respond to changing FEAD belt loads quick enough... I vaguely recall a TSB but can't be sure of my memory... (old timer thing)...... but this shouldn't depend on engine load.....

Unless you drive a LOT, this should still be covered under the engine warranty (5 years / 100,000 MILES but there is a $100 deductible...).

Thanks for your input guys...........vehicle is still under warranty........hubby says let the Ford guys sort it out................any other comments on the 6.0 liter diesel would be appreciated tho'

Denise

denise hort> Recently, while towing a fifth wheel through the mountains our 2004