You've got a heck of a mess on you hands there but all is not lost. Here's the deal.
1. You've got a really badly jammed OD. The OD mainshaft is jammed into the planetary gear.
2. This prevented the previous owner from being able the remove the planetary gear from the T-90 mainshaft.
3. He just cut the whole thing loose from the T-90.
Here's the result
Note the gear marked as part B in the Photo. That part comes out of the planetary gear but only after the OD mainshaft (Part C) has been removed from it. If you try to pry part B out of the planetary gear (Part A) you will ruin one or both of them.
Here is an OD that has been properly removed
Note the OD mainshaft (Part D in this photo) has a gear that fits inside the gears in the planetary gear. Also note the bearing on the shaft (Part C in this Photo). This is the nasty little guy that's holding everything together. As the gear meshes with the gears in the planetary gear this bearing is forced down inside the bearing seat (Part B in the previous photo). It is a press fit and the only way to get it back off is to pull it out of the gear. The bearing will not come off the OD mainshaft while it is still inside this gear. You must first pull the bearing out of the gear. Now you are asking yourself, "How am I going to get that thing out of there?" Here's what you do.
1. Reinstall the OD housing and gears back onto the OD mainshaft. You can leave out the synchronizer springs and plates. Make sure you reinstall the spacer on the end of the shaft.
2. Now install the nut on the end of the OD Mainshaft.
3. This will butt the backside of the planetary gear up near the OD housing.
4. Clamp the planetary gear in a vise using a heavy cloth to prevent marring.
5. Using two large screwdrivers at the two points labeled as Part B in the last photo begin to work the planetary gear back and forth from the case. Take your time. It may take a long time to get it out. Do not use extreme force. Remember that the case is aluminum and you could break it if you aren't careful.
Once you get the OD mainshaft out of the planetary gear you will be able to see the special clip and retainer inside the gear. You can see them laying between the two main parts in the last photo. Remove those to access the planetary gear nut. Use a 1/2" drive extension to break that loose and unscrew it from the T-90 mainshaft. From there I think you will be able to see how the rest comes apart.