J Just replaced the flywheel on my 1997 F150 4.6L. Nothing else was done. I tested and found nothing unnormal. However this morning as I was driving to my job it suddenly stayed in neutral. Transmission is not engaging, not at all. I have further checked and found there is absolutely no line pressure. I checked the front pump and installed new gears, but problem still the same.

I think you didn't plug in the shift solenoids. Look along the side of the transmission for a plug hanging their.