Certainly use a new gasket upon re-install, then be sure to torque the bolts in the proper sequence in the service manual. No extra sealant needed.

 

had the same problem but as i looked further the very bottom right allen was still in.

 

All bolts are out. Broke two razor blades. Tried tire iron throught derby cover. Beat it with a block of wood and hammer. Tapped around with mallet. Still on there like a champ. Trying these methods without marring chrome or case. Looks like I have to call it a night. Don't be afraid to throw out any and every idea you possibly have.

Is there dowl pins I have to worry about?

 

A buddy of mine had this issue last summer. I stuck my hand inside and pulled while he took a rubber mallet and tapped along the sides. While pulling I put my feet on the frame to get leverage. Needless to say when it came off I slid back. There was no silicone on his Heritage so have no idea why it was like that, just was.

Also, I know you said all the bolts were out but look once more for GP. There is one right behind the passenger floor board. It would be easy to miss that one or the bottom right.

 

yes ther is a dowel of a type..2.. but a bolt goes through the center of the front 1 ... holds the gasket & outer primary in place till you get the bolts in.. here is a pict of mine when I replaced the compensator ...

 

Try using a heat gun, around the edges, on the primary cover, only, to cause differential heating and expand the outer cover, against the inner. Also you can use a tool, called iSesamo, that I use to open iPod cases with. It will slip between the covers and gasket and you can slide it around the cover, prying between them. iSesamo's ultra-thin steel design allows for easy entry into microscopic seams.

http://www.newertech.com/products/isesamo.php

 

Can you take a picture of the cover and post it here?

 

Maybe a slide hammer on one the derby cover screw holes might work.
Dont whack it too hard.

 

Take 2 bolts and start them back in a couple turns. Then get an old pocket knife, or one you dont care about whacking on, and put the edge of the blade along the gap between the outer and inner cover. Then tap the blade down into the gasket with your mallet. Might have to do it in several locations. The blade will act as a wedge and push the cover away without damaging the covers or having to whack against a chrome cover. The bolts will keep the cover from dropping on the floor.

 

I would try to use either a gear puller or something like a pulley or harmonic puller. Put in through the Darby cover opening and apply enough pressure to simulate the same force as someone pulling on it really hard plus a little more. Put some padding on the floor to catch it when it pop off, so it won't get scratched up. Then smack it really good with your mallet and/or 2x4. Keep adding more force on the puller every now and then.