Here are some observations from repairing problems with a drive motor on a 763. First, if you are filling up the chain case with fluid you need to replace the seals. There are multiple threads on how to do this. I believe that if you are replacing the seal you should make a tool out of 2" pvc and use electricians tape to build up a gradual taper so that the seal gently slides into place. I've tried simply hammering a seal into place as well as taking it to the local Bobcat dealer and neither time was the seal working after installation. I've now done 7 of these using my tool and they have 100% been good. If you are "resealing" a drive motor check out this YouTube site. https://www.youtube.com/@tetradgroup He is obviously a seasoned Bobcat mechanic and will walk through the repair procedure. *IMPORTANT* if you have your drive motor disassembled take care to not let the geroller come apart and check it for gouges as well as the mating plates. Tazza talked me through inspecting those. I fixed one mating plate by polishing using a piece of glass with emery cloth. If those componets are mostly tight and free of deep scratches lets asssume they are good before spending $2000 on a new motor. I purchased seal kits from Loader Parts Source. They work fine. I find that the small oring that fits between the first two components is a little undersized and have use a thicker oring. I validated this with pressure testing the motor. I do this now using a hand held hydraulic pump while blocking off the opposite port on the motor and build pressure up to 3000 psi (be very careful). If there is excessive leakage something is wrong. We had leakage from the inside and couldn't find a problem. The larger oring solved it. It is between two plates that do not move so I think we are OK and have many hours on the machines we repaired. that is all hope it helps.
