Chrysler a518/46re transmission

2003 Dodge 3500 van slips going into 2nd. If I let off the throttle it will shift if not it will go back and forth 1st to 2nd to 1st ect. Trans shift is electric controlled by the pcm, but no check lights on. vss? and how do I test it.

thanks, kris

have you had battery or charging problems lately? You may need to have the transmission control compter re-programed. Just a wild ass guess.

Wouldn’t that be the main power control module (computer) that preforms that function? However no bat. or charging problems.