Cadillac Repair: I HAVE A 1990 CADILLAC SEDANDE..., shop mechanic, catalic converter

Question
I HAVE A 1990 CADILLAC SEDANDE VILLE, 4.5LTR. I CHANGED THE TRANSMISSION FILTER AND GASKET. nOW IT WILL NOT SHIFT FROM SECOND TO THIRD GEAR. EVEN IF I PUT IT IN D, OR 3 MANUALLY IT WILL NOT ENGAGE INTO THOSE GEARS. WHAT HAPPENED? i DID BREAK THE AIR FLOW TUBE ON THE CATALIC CONVERTER, AND I HAVE NOT REPAIREDIT.WHY DID IT STOP SHIFTING? HOW DO I FIX IT? PLEASE HELP ME!                                                                                 REALLY LOST

Answer
Hi John, Sometimes when the trans fluid and filter haven't been changed for a long time it affects the way it operates once the new fluid and filter have been installed. Another possability is there is a bimetalic spring on the drivers side inside the trans pan very close to the filter. I have knocked that spring out of position but remembered to put it back. Maybe if that spring were left off it could cause shifting problems. Breaking the air tube could cause the catalytic converter to fail prematurely so I would advise getting the tube repaired but that shouldn't stop the trans from shifting. If the spring is in place then you will need to consult with a trans expert or trans shop mechanic. Sorry I can't offer any more advise. Bill