Mercedes E4 30 transmission making loud whining noise and losing power

 Mercedes E4 30 transmission making loud whining noise and losing power I once had an issue where my radiator busted I was overheating and all of a sudden transmission fluid leak. Transmission lost power. I didn’t run it to cause any damage. I had the radiator replaced and it fixed The transmission leak. Then the replacement radiator somehow had a problem and begin to leak so now I am in a situation where I can’t afford to replace it just yet. But then all of a sudden  my transmission starts to slip a little then loses power now he makes a whining whining sound and loses power but there is no fluid leaking. I’ve done a little research but I’m not a mechanic but I understand what it could be. Does anyone have any advice . I always tell my friends I’m driving a Mercedes but I’m not rolling a Mercedes there is a difference. I can’t really afford repairs right now. Please help! Anyone?