80 300SD 4 spd tail housing removal (in car)

[VegErl]

My 1980 300SD 4 speed auto trans has a crack in the tail housing and I'd like to swap it out with a good one while the trans is still in the car. I have the drive shaft removed along with the trans mount and X-member. The tail housings bolts are out and the housing is loose with about a 1/4" gap between the main housing and the tail. But it won't come off any further. It appears that the output shaft is staying put. What's the trick? I hate to pry on it and bust something. Any advice would be appreciated.