1993 BMW 740 I 180,000 loud sound Transmission?

My Car has always ran very good. Recently at the same time two things started to happen. They may be related Im not sure. First when I start the car it runs great for 5 seconds then go to rough idil. When you give it gas seems to run fine. Check engine light is on. The same day this happened I started to hear a high pitch sound that got louder and louder. Sounds like belt noise but thats not it. I jacked the cat up and pin pointed the noise coming from where the tourk converter meets the transmission. As you know with BMW many have the transmission that you never refill fluid. Also if your in park and you let the rpms get to low as in rough idil that will activate the trans program Transmission will stay in just one gear. As long as i keep the idil up therefor keeping the volts up trans program does not come on. I feel that the loud noise is somehow putting a load on the engine causing the rough idiil. I dont know what to do. Cant drive the car with that load noise its really loud Is there a bearing in there that goes bad please help