Soak the broken piece with Kroil or PBlaster and use an easy-out. I'm sure others will chime in with different things to try.
'03 Mercury Marauder (The Blackbird)
Trilogy Motorsports supercharged #61
Too many mods to list / Driveway Queen
'04 Grand Marquis LS Limited Edition (Spruce Green)
Daily Driver (Thanks, Adam!)
'00 Grand Marquis GS (Silver)
Rotted frame and broken transmission crossmember