Volvo XC70, Grinding Noise

Sounds like c/v axles (front drive shafts) they will make a clicking sound normally when turning sharp and accell at the same time at slow speeds / look at the axle boots and look for grease on the inside of the front wheels leaking out the axle boots

Have either wheel bearings or hub bearing assembly changed. recommend you do both sides.

Grinding Noise Upfront: Check the heat shield between the downpipe from the engine and the bevel gear, sometimes the heat shield drops on the driveshaft and makes alot of grinding.

Grinding noise in the back: Check your tire pressures, Back tires may not be spinning fast enough to keep up with the front tires. This cause a lag/drag on the differential, propshaft and the propshaft bearings and the Viscous coupler. All tires must have the same rolling diameter.
My solution: By four new tires or Adjust tire pressure (put 40 psi in rear) and drop front tires to 38, then drive (Still have noise?) drop to 36 -->34 until noise disappears. Keep a constant eye of your tire pressure; The best (and least risky solution) is to have four new, well inflated, well rotated tires. Note: You should always follow the recomended tire pressure under the gas door (Notice that the front tires can be at PSI 36 while the back can be at 41 PSI).

I had something similar last week and when I checked, it turned out that the strut mount was broken on the left side...

I have a 1998 v70 xc awd there is a noise like something hitting the propshaft but after crawling under and having a look i cannot see anything wrong .Can anyone help