Ok, first off 89 xj auto 4x4 4L.
From the front left, there is a "skroing" noise when it goes through dips on city streets. It doesn't do it on potholes or rough dirt roads, only when the wheel travels down then up gradually. It won't do it at all if the outside temp is 90 or above, but gets worse as the temp drops. It really sounds like a coil spring issue but it is not rubbing anywhere. It stayed the same after I replaced the control arm bushings.

Looking for some ideas here.

 

Check the condition of the upper spring isolators.

 

how are your shocks? x2 on the spring isolaters

 

visually, the isolators look fine (not dry and cracked), shocks are brand new.