I hae a 1989 Grand Caravan, we jacked up vehicle and replaced front rotors brake pads etc, let it down backed out of the drive way to test brakes, when I got to speed enough to change to 2nd gear, it would not change, THEN when I got it home and parked it waited about 3 seconds , started her back up, No reverse... Mind you it ws fine when we parked it to put new brakes on.. What could cause this crazy transmission problem??? any body have a clue?

Check the vacuum hoses going to the transmission actuators for changing gears.