FFC, did you take your shifter out to add a quart? Or is there some sort of access hole by the shifter? If you removed the shifter, chances are some bushing material may have gotten lodged in a bad place, or a bushing fell out and you didn't notice. I would re-check my latest work if it were me. Things like this happen all the time at my shop, so don't feel bad if it was something you did. We've all been there.
