It's funny, because we are on "very high" when we leave our gravel driveway. The car lowers once we reach speed. And this is where my wife complains about the noise under hard acceleration.I thought I read in a different thread that suspension height setting (eg. set to 'high' or 'very high') was responsible for rumbling during hard acceleration. I have felt it myself just yesterday and now that's twice in 2 weeks. I did have my suspension set to automatically raise to 'very high' in the park I was visiting, but I would have thought it would have lowered to 'standard' by the time I was leaving the park, but based on the rumbling, it was still probably on 'very high'.
I'll just have to monitor my suspension setting a little more closely the next time I feel the rumble. The best way I can describe it, is that feeling when you hit the brakes hard on a slippery surface and the ABS brakes kicks in to prevent skidding. Also, about 3 weeks ago I had my vehicle at the SC for a seat belt issue and they also checked my suspension (on their own initiative) and found that it was fine.
I'm driving the X later this afternoon and will try to drop it first, see how that goes.