I don't want to spend 15 minutes threading those knobs back on the splined rod again every time someone sits in the back.
.
Maybe I spent too many hours listening to King Crimson ...... (just listen to Deer Magnet !) ............ ???
.
but I belive the adjustment knobs do not thread on to the rod - but (instead) push on to the rod ........... and there will be an audible 'snap' when the knob is installed properly and fully ......