I have a semi loud humming noise coming from underneath my 2010 f150 4.6 2v 4 sp. I thought it was the stock michelin tires. But I just got new rims and tires and it stills remains the same. It happens when I'm driving about 35-45 mph.
Other mode include a sct x3 and duals. I just hope its not the trany the truck drives and shifts fine, maybe a wheel bearing? I hate taking it to the dealer, the don't know what the f their doing last time they broke more than they fixed.

 

Does the hum go away when you let off the gas?

 

No. It goes away when I slow down past 35

 

What if the humm does stop after lettin off the gas?

 

I know it's the diff,but witch part? Oil leaks from bearing
At the drive shaft. Makes a horrible screaming when I push on the gas.
I have been driving it a little and was wondering if I'd be better
To go ahead and replace the entire rear? I can get one
Used for 300$ in good shape.also seems to me that it would be faster and easier?