96 mercury sable tranny problems

It's suppose to say P for park R for reverse not e and N for neutral not m i hate cellphones sometimes stupid autocorrect

I changed the neutral safety switch on a 97 Sable that when already rolling about 20-40mph in second (gear selector in OD) and giving it gas it would down shift hard into 1st (not over slipping though)and it stopped it for the most part, I had to adjust it a few times to get it much better but it will still down shift simi-hard at times but no where as hard as before and has not gotten worse (its much better). I know this is a little different than yours but may help. Its on the trans/engine connection just under brake booster toward the motor some. Only did it in OD.

Now the car won't shift out of first gear. The transmission fluid looks perfectly red filter looks brand new it's got over 200,000 miles on the car I just changed the VSS sensor and the VSS sensor wires were bare and touching bare metal so I change the connector and the VSS sensor but the car still won't shift out of first gear it'll go into park reverse and neutral just fine but when you put it into overdrive or drive it'll get at about 25 miles an hour then it revs all the way up and won't shift into 2nd at all and a few hours before that the speedometer stopped working and the odometer don't work at all anymore.

What causes this to do this my car does the same thing