'93 ES300 transmission housing? cracked & fluid is leaking out
 

I could use some expertise, please, as I do not have access to a service manual: My 1993 Lexus ES300's transmission has a crack in the housing and is leaking transmission fluid. Easily gotten to through the driver's side front wheelwell's panel you can see this hairline crack rising upward from the center. It looks like a screw, which used to be in the very center of this round housing, has broken off partway down in it's screw hole in the housing.
Anybody seen this before? What did you do? and what can I do? I appreciate any thoughts you have on this, as well, it's my old car that has 270K miles and I'd like it to last forever. Any ideas?

take some pics but if the housing is cracked then replacement is the only way to stop the leak if in fact it is cracked and leaking there...