A new Vibration

You wouldn't have hit whatever it was hard enough to throw the alignment out would you? Could check that or maybe even damaged the tire if it was something large enough. Hope you get it figured out

 

what kind of vibration? does it shake the wheel in your hands or do you feel it in your butt? is it at some speeds and not others? does it come when accelerating, decelerating, holding steady throttle or does it not matter?

 

I have same VN670 with VED16,535HP,1850 torque.6 months ago interaxle driveshaft disshafted from RRaxle at 65MPH.It was awful.So check your driveshafts

 

Nope,it was not driveable,was towed to nearest Volvo service.And not noticeable shaking before incident

 

Well here is a bit of info for general guidelines.

U-joints will usually grind when you let off the throttle. Same with carrier bearings plus they tend to queek or rattle a bit at VERY low (creping) speeds

tires that are out of ballance will generally shake at one speed for a few mph spread then stop then shake again at another certain speed for a few mph

Sounds to me like a drive tire out of ballance. If it is getting worse as you go then you may have a tire coming apart. You could have hit that object with your drives after it hit your tank causing it to loose a piece of rubber and it may be getting worse.
My truck right now has a rear wheel out of round and it wil jump the rear of the truck at high speeds but the steering wheel is dead steady