I recently purchased a 1995 Cadillac Sedan Deville 4.9 liter. I noticed that while slowing down to stop, the transmission violently shakes while it tries to go into 1st gear (obviously, from 2nd). The shaking happens at around 16 mph and stops a few seconds later after it makes it to 1st gear. It has no other transmission issues other than this...drives down the highway like a champ! I found a few forums with people having the same problem as mine, but they were old posts and no one posted their results for the repair. I want to keep this caddy but I need help figuring out the tranny issue.

 

Thought I should mention that upon starting the car, there is a slow, steady banging sound coming from what sounds like the tranny...for all I know, it could be the air ride compressor, as I don't know where mine is located but I have a Service Air Ride error that always stays on. If it's the compressor, I don't care, but if it's the tranny obviously I do. It goes away instantly when the car is put in gear. I'm gonna need some help.

 

From the description, it sounds like it could be the converter clutch(TCC) not dis-engaging, and trying to kill the engine at a stop. You should pull the codes to see what codes are stored first, then go from there. TO get the codes, with the key on, press the "OFF", and "Warmer" buttons on the climate control panel at the same time, and hold them down for about 5 seconds or so. The information center under the speedo will show any/all codes present, starting with Engine/trans codes, then Instrument panel, HVAC(A/C), Traction Control, and Suspension.
Post the codes you find, and we can go from there.