Rear differential fill plug cannot get out
 

I have a 2005 Honda 400 ATV. I was told needed to change the front and rear differential oil and thought I would do it. However I started on the rear and the bolt that holds the fill cap in position will not come out. The metal is so soft regardless of what I use it just peels the aluminum I guess it is away from the bolt. Does the bolt turn any differently than left to remove it and right to install it. Now the bolt is rounded off, any suggestions as to what I can try now. I have even tried channel locks they slip and bring metal off the bolt.

Any help will be appreciated.

Impact gun?

I am not familiar with the 400 atv, what size was the head?

You could possibly try a pair of vise grips or some kind of pliers that have rounded teeth. I have used vise grips on many things where the head was rounded off.

look at the head of the bolt, Clockwise tightens, counterclockwise loosens.