Need help getting engine off

i think i screwed it up first off my snap-on rachet extension looks like a mushrom it was a 3/8 but now it looks like a 1/4in drive, also i cant screw the nut on any more and it broke my walmart impact wrenchX(X(X:)-/:(
 
You probably have it binding if you have it half way out. Check the swinger, if it looks crooked, you will have to get someone to pick up the back of the bike from the grab bar. Also, make sure the rear shock is off. You can also get some stuff that's called Freeze Off. It freezes and shrinks metal fasteners. It comes in a spray can like PB Blaster. Good luck!
 
Sounds like the end of the bolt is mushroomed. If that's the case, it's binding up on the swinger bearings and / or the engine. Try to cut the other end of the bolt off and pound it back the other way. Don't mushroom that end or you'll really have problems.