Good day to you all.
I just got back from my first trip with my F350, and pulling my 28' travel trailer. It was about a 200 mile trip each way, with hills, curves, and flats to deal with. While the truck pulled the trailer with no problem, there was a strange noise that I heard coming from the engine compartment somewhere.
It seems that when I was on the gas, the engine would pull with no issues, but as soon as I started to level out, and the tranny would up shift (drop RPM's) a funny sounding "squeel" would come from somewhere in the middle to right side of the engine. If I lifted off the gas pedal for just a second, the squeel would go away. And if I stayed in the gas, the noise would eventually go away. Getting up the hills there was no weird noise. I sometimes here this (I think) when I get off the pedal, after stomping on it, without even towing.
I'm hoping that someone out there in FTE-land can help me figure out what is going on here. My first guess is that a bearing or whatever is going out in the turbo. But since I am very mechanically declined, I'd like to hear from you, and see what your thoughts are, and what I should check.
Thanks in advance to you all of you for your help.

 

And oh yea, I only got 10.6 mpg on the on-board computer, which means it's really like 9 mpg while pulling. I expected around 15!

 

Never trust the overhead, it does weird things - even in stock.

You have no gauges, scan tool, or inexpensive phone app to link to the OBDII port for intake/exhaust pressure readings? You can't take a recording of the sound and post it on YouTube? Somebody would to have fought that sound before, in order to recognize it from your description.

It's possible it was fan belt squeal from warming up after a grade and you heard it in OD. It could be turbo bark when you let up. The bushing on the turbo is bathed in oil, but it could be rubbing on the housing. When was your last air filter change... is the filter minder pulling in?

You could have exhaust/turbo leaks. Do you have soot anywhere under the hood or engine? (ya really gotta look)

 

My first thought was compressor wheel contacting the housing. I've heard that twice on my truck with just the right throttle, load, and boost pressure. The only difference on mine is it was under high boost and acceleration, not when shifting down or locking the TC.

Pull the intake tube off the compressor and check for play in the wheel. Up/down, right/left, in/out.

 

As far as mileage while towing, you don't soud far out to me. I tow a 32' fifth wheel (high profile) and can get 11.5 or 9 depending on head/tailwind on the same route (rolling hills along Florida I10). I usually pull at 70 because I have more torque than I do at lower speeds, and don't have to shift down as often. My truck is tuned though, and that's a big difference in power than stock. You'll probably do a lot of shifting in rolling hills.

 

Are you pulling with the OD off? Leave it on. Do all of the little things to get your mileage up. check boots for leaking, etc. there is a thread with suggestions.

start with the belt and pulleys for the squeal.

Why would you say that you are mechanically declined? With friends on this forum helping you out, the job(s) are already half done.

Welcome to the forum.