Don't run it with no or way to low fluid! Other than the leak, how is the trans doing? Strong, shifting well, etc.? If the trans has been giving me no problems I would pull it and clean it up, change the seals, front and rear, drop the fluid while its out, clean or change the filter, drain the convertor and put it all back together. It is not a real hard job to do, if you are handy do it yourself and save the bucks.