alright will try angling the diff pinion up tomorrow after work to see if it improves the situation... (fingers crossed)
im pretty confident its not the wheels bearings nor the pinion bearing as suggested before as the ute was running sweet with the a12 with no vibration prior to the conversion...
wish it was that simple but i think its my (not so) handy work thats caused it..
anyway thanks again for all the suggestions so far... just shows how good this club is..