No gears work

What is your question?

The car running I put it in reverse drive third second first nothing goes into gear no it's like neutral all of them and it's flashing between gears on an instrument cluster what should I check

What makes this problem better or worse?

Doesn't get better or worse does the same thing always I was driving and then it just all of a sudden seem like it was neutral and stayed that way

How long has your 2003 Mitsubishi Diamante had this problem?

All of a sudden