I own a few 4 wheel drive vehicles (mostly Jeeps) and went ahead and finally got a Range Rover '02 4.6HSE. I've had it for a few months and took it into some muddy conditions for the first time where 4 wheel drive was required. While bouncing up and down, there was a distinct clicking noise coming from the front of the car somehwere under the hood (left side?). I wondered whether or not it was the air compressor continually adjusting perhaps as I was driving? Once I was on level ground/pavement it was not happening at all and I was still in 4 wheel drive. It was a bit loud, so I wasn't sure if that was normal or a sign of something more serious that should be checked out immediately. Again, this was only while in muddy un-even conditions and on flat ground I heard nothing, despite still being in 4 wheel drive. Any advice or info is greatly appreciated.