As the title says 1990 chrysler lebaron 3.0 v6 with 4 speed auto transmission.

Worked fine up until Friday evening coming home from work (20 mile drive), Both highway and regular city streets. Came off the highway and was doing about 35 - 40 and then trans started surging as it came up to where it should shift into overdrive.

pulled the battery cable and tried to reset the computer that way and still same problem. bought new input and output speed sensors for the trans and had the battery out while changing those. Still same issue. 1-2-3 shift fine, just when the overdrive is supposed to go, it bumps three times and then stays in third.

The only thing done on Friday was that I had the ac charged with freon. The trans fluid has been changed by me as well as the filter and yes I used the correct synthetic fluid.

Looking for suggestions and will be happy to answer any questions.

Jim