Transmission problem

The tranny is a generally a closed system. There is a drain and a filler plug on the tranny. They don't usually need much attention but should be checked occasionally.

Now the problem with the car. Answer this question. When driving prior to this would the car seem to slowly get up to the speed you wanted? Would it if you pushed the pedal down especially in first gear not burst ahead as expected? I am thinking that the clutch was slipping for you and has finally given up. You have a cabled clutch I would surmise with decent pedal pressure, right? I am willing to be based on what I have from you that the clutch is now in need of replacement.