That sucks dude. Here's a link to an exploded parts diagram fro your tranny. I'm pretty mechanically inclined and i don't think I'd touch this thing with a ten foot pole.
http://www.secured-transactions.com/...Page_Number=41
If you want to try it DIM has parts for a rebuild.
http://www.skidim.com
and here is the link for the rebuild parts page
http://www.secured-transactions.com/...Page_Number=14
They can probably tell you what is wrong and what you need as well as get you a sergvice manual for the tranny. Or you could save alot of blood, sweat, and tears and just order a complete rebuilt.
Just remember, after pulling the tranny out you will have to take it to a dealer to get it realigned to the driveshaft or you will get vibrations.
Again, sorry to hear about your loss. I'vee been lucky most of the things to break on mine have been minor nitpicky things.
By the way, how many hours do you have on your boat?
Later,
DKJ
1992 Supra Mariah - Red
PCM 351HO 285hp - PCM 1.23:1 Transmission
OJ XMP 4 Blade CNC 13x15.5RH
"People do weird things to boats" -Unknown