6 speed "check plug" or "fill plug"

[Andylad13]

My brothers truck has the 6spd, and we wanted to see the level of fluid in it but couldn't budge the plug. Its a 1/2" square hole, to which we tried a 1/2" breaker bar to no success. We didn't want to put too much pressure on it because there was a guy at a ford dealership who showed us what happens when you try to loosen it when it doesn't want to loosen. Basically it breaks the transmission casing around the plug.

Has anyone tried to get this plug out?

 

[Ironman03R]

Never had to do one of them, but normally if I have a stuck plug in an aluminum case a LITTLE heat and some good penetrating oil will do the trick.