Volvo: 2002 Volvo V70XC AWD Cross Country noise, volvo v70xc, smooth pavement

Question
Driving on a rough road at any speed causes an erratic knocking noise similar to a loose bolted joint. It doas not occur on regular smooth pavement. It occurs only when the wheels bounce on a rough surface when driving straight ahead. Car has 43000 miles, runs perfectly, no vibration.
A regular automotive shop (non-Volvo) inspected suspension, drive shaft, exhaust but found under car components solid. No local Volvo dealer.  

Answer
This might be covered by your warranty, if it's still valid.  On 3-10-2004 a TSB was issued as follows:
A knocking (or clicking) noise may occur from the front of the vehicle when turning, slowly going over bumps, and/or entering an inclined surface (driveway, parking lot etc.). The noise usually occurs when the body undergoes a twisting (flexing) motion.  The noise can originate from the bumper rail contacting the front side member(s).
Warranty Claim Information:
Labor Op: 99037
Labor Description:  Bumper rail front adjusting
S60/V70 (01-)
Labor Time:  1.1 Hr.
You may or may not require a Volvo dealer perform this for you.
JD