squealing/whining when towing uphill

[ryan154]

i have 2006 psd with an auto trans and 15400 miles and recently heard a strange whining noise while towing a boat this weekend. it only happens when im going up a long steep hill. it starts with a few really short squeals/whines and then it does it for about 5 seconds and then stops for about 10 seconds and then it does it all over again. there didnt seem to be any loss of power and everything on the dash looked fine, and shows good boost. once im at the top of the hill and let off its fine and there are no more noises. the truck is stock other then removing the cat and muffler. any help would be more than appreciated! thanks for your time and help.

[mschn99]

could it be a belt squeel??

[ryan154]

i thought about that too but it just seems to have such a pattern to it that it couldnt be the belt. so im not so sure it was the belt. thanks for your time though mark!

[mschn99]

might be worth taking a peek at the belt anyways. Some of them shredd the fan belt, which is fixed with an updated water pump pulley....also some coolant on it could cause it...

The reason i ask is that the fan clutch will engage at warmer temps while towing up hill....and with the AC on as well, this is the maximum amount of drag the belt will see....so every time the fan clutch locks up, the belt would squeel if it had any problems...

[partner]

Thats what my squeal was, on big hills, belt was replaced, squeals gone!!!

[obert]

Something similar on my work truck... Definately not the belt, seems to be comming from the lower driver side of the engine compartment.

Under light throttle, trans in 5th and TC lockup about 33-34mph. A gentle nudge on the throttle (like on a slight up grade) holding speed and thach in the 1250 neighborhood and I get the grindy/whiny/moaning sound. Kinda like gearslap in the ZF behind a lugging engine. That is the exact scenario to reproduce the noise, will do it evrey time, but any change in the formula and all is well.
Took a ford tech for a ride the other day-- new to him; he was dumbfounded. We thought it might be some thing vibrating on the right exhaust. The truck will be in for another repair next week, theyre supposed to check it out then. I'll post findings.