Mercedes Benz repair: 1978 Mercedes 450SL w/leaky transmission, mercedes 450sl, transmission fluid

Question
I am asking this question for my parents. They have a 1978 Mercedes 450SL that has leaked transmission fluid for ages. They have taken it to multiple mechanics (Mercedes included) and no one seems to be able to fix it. Could you please offer any suggestions that may assist us in finding a solution?

Thank you for your time.

Answer
First off are you sure it is transmission fluid? red of course? I believe this year of the car was a hydropnuematic suspension so if it is not red it is the suspension fluid. but i could be wrong as far as the leak where is it located in the car? if it is in the middle chances are your gearbox drain plug is shot r someone installed it too loose. or it could be a leaking hose email me if you have any questions sfame1@yahoo.com, tell me where it is coming from and how much etc.
sfame1@yahoo.com email subject mercedes tech so i know shane pics would also be good.