We have a new ProMaster 1500 high roof with 1700 miles. Just went on a 400 mile trip and am now getting a "banging" sound intermittently that sounds like it's coming from under the passenger side mid/rear. It only does it when we're not accelerating. I had one of my guys jump around in the back and it didn't make the noise. Doesn't sound like it's the suspension since it doesn't do it when driving over bumps or potholes either. I've had trucks in the past that would make similar noises when the UV joint went bad. Any ideas? It goes into service tomorrow but I'd like to give the service guys something to go on. I've never had luck getting phantom noises resolved with service people.