1987 transmission

i have an 87 continental, for 2 months i heard a whining noise i didnt know what it was, i was driving the other day and i heard a bang and noise like it was my rear brakes, but it was my tranny. when i put it in any gear the bottom of the car sounds like a bull dozer breaking ground, sometimes i can put it in drive or any gear for enuff for me to roll like 5 feet before the grinding begins. can it be a dirty filter? also on the bottom of the car i see a cable running along side the bottom perimeter on both sides, on the driver side the cable is broken, is this a break cable? or does it have anything to do with the tranny?
thank you so much joe