Strange noise and vibration. Any thoughts?

[DavidVella98]

Hi does anyone know what the issue following might be?

This is felt mostly on low speeds and gears. It is also felt it is in free when I steer the steering to the left or right there is the sound and vibration that feels like a constantly something hitting something else ''pumpumpum'' if that makes sense.

At first my mechanic told me is the rear diff, however i went to see if this is an issue and now I'm having doubts that this is the case.

Anyone has any thoughts on what this might be! Thanks in advance.