1999 Sebring transmission question

I realize it's not an A body. Sorry.

Came into a '99 Sebring, 2.Something V6 automatic. First and reverse work ok. When it goes to shift into second... nothing, engine just freewheels.

If I stop, it doesn't want to go again until I run it in reverse for a minute. In first it seems to pull fine until it shifts.

Any ideas? Fluid level is correct, fluid seems clean and doesn't smell burnt. Should I even bother dropping the pan and looking, or is this trans probably junk?

Thanks for your tips and advice, I'm no transmission guy but I can pull a valve body and take it apart with out screwing it up too bad. Thanks again.
John