Ut oh maybe future TSB coming out, hope not.
F-250+ has a TSB for fluid leak at the selector shaft (TSB 22-2450) Maybe the 10R60 uses same parts / design in that area.
Shouldn't be a problem. The Line looks like it is the hard plastic style.
Maybe you can reach in there and discount the sensor plug it into a new one. OR to really see try to clean it off, if it did get sprayed.
Service procedure says to remove the rear bumper (of course :) ) the muffler and the trailer hitch. no mention of removing the body. The image shows the body still on the frame. You can acess all the welds with it on.