1966 Eimco 103M Transmission trouble

After giving up on used cars and graduating from Farm tractors to heavy stuff I'll need a little help here, please. I am the proud owner of a 1966 Eimco 103MC, purchased sight unseen at auction (didn't know the high bidder would bail) and now the owner. Has not run in 10 years... transmission failed.... and I still jumped at the chance to buy it. Here's the question, limited research has told me that: they have two transmissions, there might be a unidrive or a quadratorque. A brief inspection of the machine looked like a solid shaft out the front of the detroit6V going to all hydraulics (motor is backwards in machine so from front of crank aft) rear of engine (front of dozer)is encased so all I saw was I trans fill spout between my legs, floor of cab. And it's ex-Marine corp. so it's bullet proof with all engine covers 1/8" plate.... some is 1/4" (note, military number is 322833 Marines? Seabees? Serial number is 1033160) 5500 hours on the hobbs, it was used to push and pile snow at a municipal snow dump, I can't imagine that it ever loaded up or worked hard at all which is why I hoped it was something simple or operator error (Operators were minimum wage ski bums not experienced operators) I do know that one tranny has one input and two outputs one to each track so it can reverse one and forward the other at the same time.... supposed to run circles around a D7. Does anyone know? What tranny or 2 are in these Quirks, issues and things to look for. Parts sources Manuals Any help or comments welcomed Also I read that they went bankrupt before filling the gov contract and CAT came in and finished machines with CAT undercarriages, how can I tell what I have. Thank you very much