There are no replacement bushings available for the wiper mechanism on the Grand Am. The entire mechanism must be replaced.
There is a park switch that is built into the wiper motor that should properly time the motor so it parks the wipers all the way down when the wiper is turned off or between cycles on the intermittent setting. There is no adjustment for this, the new wiper motor was just assembled incorrectly. I would suggest exchanging the mechanism where you bought the part.
Whel installing the wiper arms, use magic marker or a piece of tape on the windshield to mark the desired location of the wiper arm in the off position. Turn the key on and wiper on. Turn the wiper off and allow the wiper motor to park and stop running. Turn the key off and install wiper arms aligning them with the marks on the glass, then install the nuts to secure the arms.
Thanks for the additional information. I do believe the jam up did damage the wiper motor. Try resetting the wiper blades using the procedure I listed above. If it is still parking up on the windshield, it is then time to replace the wiper motor. There are no internal adjustments that can be made to the wiper motor and park switch.
Failures of the bushings in the linkage do happen, but not that often. I do not believe I have replaced more than one or two wiper linkage assemblies on Grand Ams over the years and I have worked on lots of Grand Ams.