we'll ill sleep on what i'm going to do with this issue, thanks for all the helpful advice! i owe you one

 

Before any attempts at removal, applying a penetrating fluid such as Liquid Wrench, PB Blaster, or equivalent (NOT WD-40). Let it soak in overnight and re-apply before trying to get the fastener off. Even if you're taking it to a mechanic, just doing this step will make it much easier to achieve success.

Good luck.

 

You can grind the head off too if you can get a file or grinder in there. As '2k says don't do it unless you have a bolt handy. Grind the head off, take off the housing then use vice grips to unscrew the stub.

 

Go to Sears or Home Depot and have a sales person get you one of their extractor sockets for a 10mm bolt. This is the "cutting" socket others referred to. I wouldn't recomennd cutting the head off: From your posts, I don't think you have the mech. skills to deal with this.

Once you remove the bolt, take it to an autoparts store or Home Depot for a replacement. Confirm the new bolt is correct by using a common nut to screw both bolts into. You don't want to buy the wrong pitch bolt..

 

The head of my differential fill bolt is kinda rounded off (not completely rounded off) but hard to take off. i have already ordered a new one.
I was wonering if anyone has advice before i give it another try.

 

Did you read the posts in this thread?

 

I haven't been back to my diff. yet but you could try a large pair of chanel locks or vice grips. I'm sure there a some specialty tools you could find at Sears that would absoluty work.