Annoying hum
 

Hey everyone, I hope I’m in the right place with this but I need serious advice. I have a 2003 Range Rover HSE with the BMW motor. It has 150,000 miles on it and has just recently had the Vanos rebuilt, all of it Timing chain needs taken care of and lots of other things. It shifts beautifully and drives like a dream for its age but I have noticed an annoying hum at 1200 RPMs and 1700 RPMs. It doesn’t really matter what speed I’m going though it’s usually within the 15 to 40 mile an hour range with my foot barely on the gas. The hum sort of sounds like I’m hitting very small road turtles but you can’t feel it anywhere in the car. Not on the steering wheel, not on shift level, and not on the gas pedal. The weird thing is if you lift your foot off of the gas pedal quickly the noise goes away. The tires are balanced and in good shape so my thought is drive lines? Differential? Anybody else ever experience this problem? Thanks in advance