Yeah, my T-case section was tough to remove too.

I think the steel alignment studs corrode due to electrolosis with the aluminum housing. This results in the too-tight fit.

I banged on the steel bolts with my brass hammer for a long time (like an hour) to get mine off. It was really stuck on the alignment studs. The gasket wasn't a problem.

Try to resist the urge to jamb a screw driver/wood chisel/putty knife/crowbar/shaped charge between 'em. You may be able to remove the damage you WILL cause with a file.
If You have to use something, I'd use the putty knife to break the gasket seal. Just keep wiggling the tranny. It'll come off eventually.