You have to inspect the gears for scoring, the bearings for bluing, the case for cracks. Replace the carrier bearings. The syncros should be replaced and all of the springs because they may have been overheated. The crown and pinion probably took the worst damage so start with them. If possible inspect the debris, if any, in the case. Separate the ferrous from the non-ferrous. If there is more ferrous than non-ferrous the box may be beyond salvaging. If the dif is all that is bad then you may be OK because you are swapping it out for the LSD. Depending on how long it was driven the spider gears in the dif may be all that is garbage. If you have any missing or damaged parts you may not be able to reassemble it, many of the parts are NLA. Inventory all of the parts as you inspect them. Some parts may be obtainable from Harry or Delorean vendors. While the trans is different in the Delorean there is some commonality in some parts. Of course you must replace all of the gaskets and seals. The box is certainly worth trying to save but if you need a lot of parts like gears, be prepared to spend a lot of $$$$$. First step is to see what's missing and then see what is beyond reuse. Find out if you can get the bad, missing parts and if you can what they will cost. Good Luck, you will need it.