2002 Dodge Neon will not shift out of 1st gear what should you do?

With an automatic transmission, then? You'll want to take the car to the dealer (since it's still covered by its driveline warranty) and have them fix it.

Sometimes it may have nothing to do with the transmission. I had a 2004 neon that needed a camshaft position sensor. Wouldn't shift out of first gear until I replaced it. There is some sort of safety mode built into the pcm. Is an engine light on? have that checked out first. Dont replace your tranny because your cmp is bad.