Hello all. I recently purchased a 99 f150 4.6 4x4 auto extended cab. It had a bad transmission. Replaced the tranny with one from a 98 that I know is good. Got it all back together and took for a drive. Runs and drives great in first gear. In drive as it shifted in to 2 gear....it felt like it locked right up or like it was slammed into reverse. I quickly threw it into neutral. I put the shifter in 2 and it moves like a foot and stops. Back up and it will move forward a foot and stop again.

No clue what is going on. Need some ideas. Any help would be greatly appreciated. Thanks

 

I've seen one do this before. It was a brand new rebuild. The intermediate one way clutch was installed backwards so the one way action didn't happen. I don't see how this could be your problem if it was a known good transmission that wasn't torn down since it last ran.

 

Yes I pulled it in good working condition. The local parts yard database shows that 99 and 98 4r70w trannys are not interchangeable. Don't know if I believe this or not. Can swap the electronics through the pan?

 

You can swap the electronics through the pan.