Weird knocking when turning (full lock) left and right directions/sides?

When I turn left or right and I reach the full steering range in either direction, there is a fairly loud, clunk knock sound. The sound is irregularly and doesn't happen every turn, it varies in severity seemingly at random. Although there is at least one knock each time, sometimes several in concession. Turning left seems a little worse than right.

I think the suspension has had a high lift and there are some larger than stock Mud tires on the rims.

I hope I'm right in thinking that the Tacoma model is the US sister of the international
Hilux model. I'm based in Australia and that's what we call them here.

Many thanks,
Ryan