I have a 2010 Mountaineer Premier AWD V8 47k miles. On acceleration there is a hum/vibration in the steering wheel and the gas pedal between 30-50 mph. This is my third Mountaineer and I have never noticed it on the others, I just got this one about 2 months ago. The others were V6 models but were AWD. When I turn the 4x4 to the lock mode there are various noises/vibrations coming from the front of the car while it accelerates and also when turning.

 

did you ever figure out your issue? I am having similar issue but mine continues even at highway speeds.