JoeyGladstone

Just some background info. I purchased a used E350 from a private dealer about 2 years ago. It is an 06 and came with about 22,000 miles. The car has about 43,000 miles on it now. I was driving the other day and noticed the engine had been making a low grunting noise while driving. The faster the car goes the louder the noise gets. When the car isn't moving the noise stops. To be honest, I don't know how well the previous driver was with the car. I was wondering if anyone could help me out as to what may be the problem. Any tips in this situation would be very much appreciated, thanks.