2006 XJ base.

My windshield wipers overswept and would hit the pillar on the drivers side. When I had the car in for a checkup, I mentioned it to one of the mechanics, a guy I really like. He looked at it like Dr. Freud, stroked his chin and said "there was probably ice on the mechanism and when the wiper couldn't move, it stretched the motor". He lifted the wiper and re-seated it so now changes direction about 3" from the pillar, but on every downstroke, it hits the plastic housing under the bottom of the windshield with a loud smack.

Is there another adjustment that I might do to get this to swing in the proper range without a "smack" at one side or the other?

 

Just move the arm a little till it clears both sides

 

Your wiper seems to be the same type as my X308 - the attached pic shows the procedure to lift it off the spindle and put it back (a teensie-weensie bit further round!) -



You might need a little puller from Ebay (a few pence) to o it easily)

 

There is a measurement in JTIS, its 56mm from the cover panel on the drivers side and 61mm on the passenger side at the wiper tip.