Why is my Transmission not shifting correctly after a few miles?

What is your question?

I hear a little like grinding or electrical shock sound when shifting into reverse or drive. It will drive fine for a few miles until it warms up and you stop at light and it down shifts then it gets stuck in a low gear and will not change into a higher gear. No leak

What makes this problem better or worse?

It's worse when hot

How long has your 2016 Dodge Grand Caravan had this problem?

A week