1987 Cadillac Brougham

Shakes or Wobbles problem
1987 Cadillac Brougham V8 Two Wheel Drive Automatic

When I start driving my car there is a fluttering sound coming from underneath of the car. After a while when I try to stop the car acts like all the gears wont downshift until the car slows down and then the car wobbles and shakes when I slow it down. All the gears seem to downshift at the same time. The fluttering gets louder when I accelerate and makes the car shake unless I give it extra gas. The car never cuts off but shakes like it will until the gears shift down to first. I heard it could be the t/v cable but I dont know. It seems like once the tranny gets hot then the downshifting and upshifting gets crazy. Please help cause the car runs fine except this problem. Thanks.