WM - You can crawl under there and check some stuff yourself if you are game, just remember to put large block of wood between front end and frame rail in case air bags fail, this will keep you from being crushed.
If broken shock it will be visiable, if seriously worn front end part, you should see a lot of shiney steel around the joint of that part.
If you dont see anything out of order, take it to a reputable truck front end shop, and have them check it out. It also could be a rear suspension part and you are feeling/hearing it through the coach.
FWIW story - we stopped at rest area in ID coming home from HH training. When we started out again, heard loud air hissing noise from under the dash area. Listened while going down road, and could not identify where noise was coming from, rear, front, we could not tell. I had EM's phone number and he recommended we check the CAC High Side boot in the engine compartment and low and behold, that had a nice big tear in it, and we only found it once we physically inspected the boot. The noise sounded like it was coming from under the front end. So the moral is, noise in one of these is a funny thing, do a whole frame/suspension inspection to be safe and sure.
Monty & Janet - 2007 Alpine APEX 40 MDTS
S/N - 75715 - Retired - Master Certified RV Tech