Cant get physics constraint to maintain distance

I’m trying to use a physics constraint to tie 2 physics objects together. As the screenshot below shows, the ball rolls around and the box is supposed to always hover above. I got the angular motor dialled in right but I absolutely cant get it to maintain the linear constraints. If the ball starts moving, the box starts to drift or lag behind. Its not by much, at full speed the box seems to lag behind by about 50 units but its still very annoying. And worse, the linear motor doesnt seem to even try to correct the drift, no matter what settings I try. Is there any way to just completely lock it in its relative location or set the linear motor settings in a way that its not allowed to drift laterally?