Tranny fluid loss on 86 760 Turbo

Hi this my first post ever, please bear with me. Here's the situation. I have a 86 760 Turbo (automatic) which I purchased 7 months ago. The turbo is bad and I need to find a good place to purchase a used one. Thats not the main issue. After one month of owning it I was losing tranny fluid quickly, so I had a mechanic replace the ring seal I believe. After that everything worked fine. Around Christmas I took the car on a long trip. After that trip the car began smoking everytime I turned parked. Now It smokes everytime I come to a stop after getting off the freeway. It continues until I turn off the car. Once I turn the car back on again there is no problem as long as I stay on city streets. It is also going through a bottle of tranny fluid every 4-5 days. The smoking happens somewhere near the catalytic converter. The leak looks like it may be coming from under the front passenger seat. I was trying to make it a do it yourself type job if I can figure out the problem and buy the parts myself I'll take it to a different mechanic. All help will be much appreciated. Thanks in advance!!!!