Steering 'jump' at around 50

Hi All,

Got a defender 90 with 2 inch lift and big Goodrich all terrain tyres.

When I get to around 55 the steering seems to pull or 'jump' not very descriptive I know but that's it

All is ok if I am accelerating but when I take my foot off the gas I get the 'jump'.

I've checked the bushes etc. today and all looks ok apart from the ball joint on the end of the steering arm, which has a bit of play, could this be causing it?

Steve

could be, it does sounds like worn steering components, give it all a good tug