It's been a while since I've worked on a T250, can't remember how it's laid out inside. But typically, you would raise your cab to view the machine components. Find the drive pump in the center of the machine, there will be 4 large hoses coming off the drive pump, 2 will go to the left drive motor, the other 2 will go to the right drive motor. Follow the 2 hoses to the right drive motor and you'll see where they go through the outer frame to the drive motor.
There will be a small diameter hose in that area, along with the large drive hoses, that would be the case drain line for the motor. Follow that small hose back into the machine. Somewhere along its path, it will connect to a small/round aluminum cylinder in the line, that would be the case drain filter/strainer. You remove that filter from the connection to drain hose, be sure and have a #6 JIC plug to put in the hose connections or you'll lose some oil.
Once you get the case drain filter removed, it has a hex end on it that allows you to take that cylinder apart. Inside there is a strainer screen. If there's a lot of heavy metal debris trapped in that filter, it's a good chance your drive motor has grenaded inside.