148,00 miles... Trans was replaced before I bought the truck. I knew it had to be shifted manually and thought it may be a simple fix. Shifter has push button overdrive, starting out in first, second, then third does fine but never moves into overdrive. Can anyone please lead in the right direction as I would like to fix it myself. Thanks for any feedback

1992 F150 4.9 E4OD

 

The first step is to read the codes stored in the computer's memory.

 

Yeah that's definitely coming this weekend. Just wasn't sure if anyone knew of a no brainer go-to place to start. Thanks Mark