European Yaris Possible u joint clack noise when I put into reverse.

[dogsridewith]

I haven't for awhile, but am not alone here w/ an apparently good condition Yarii exhibiting a sort of freeplay looseness getting taken up at full lock. Not necessarily always in reverse, and can be more of a feel in the steering wheel (car, seat of the pants) than a noise.
Seems to be a yet unexplained mystery.
Need to get a look at things in full-lock, but low car is hard to crawl under and can't run up the ramps at full-lock.(duh!)
What parts are real close or touching? Is something in the linkage going over-center?
Maybe my prior owner never got to full lock in the first 135 k miles, and there was some dried grease crud near end-of-travel on the actuator of the electric assist?