2004 FX4 SCREW 70k miles
I have noticed a high pitched whine noise that increases with the speed of the engine, at low speeds. Ford dealership says its the trans and drive it until it breaks. I thought I saw a post on here about someone with the same problem but turned out not to be a trans problem. Any help?
Thanks

 

i just had the same problem. my tranny has 200k miles on it. took it in today, turned out to be the u joints

 

Try turning the t-case switch to 4 high and back to 4 low. That was what I found on my 05. There are load of posts of people wth really loud t-case noises in here. I feel lucky that I solved my noise with a gear case oil change. By the way it uses Mercon, not Mercon V for the transfer case.

 

Just to confuse your even more, I had a whine/howl come from mine shortly after I bought it new and it turned out to be the rear diff and gears, I had a mis-aligned rear end and it was wearing out my gears. Its been fixed and and haven't had a problem since. I don't remember the mileage I had on the truck but it was much less than what you have. Good luck!

 

You may be thinking of my thread from several months ago. I had a high pitched whistling noise that would change pitch as the RPMs changed. I thought it was the tranny because it sounded like that's where it was coming from. Turned out to be a bad tensioner pulley bearing. Take the drivebelt off and start the engine to see if it still does it.

 

https://www.f150online.com/forums/sh...ight=tensioner

 

I only hear the whine when it's in gear.
I'll try the drivebelt and see what happens, as well as switching to 4-low and back.