My 2007 trailblazer is making a high whining noise by transmission. But its stops whinning as soon as i put it in park. When i driving down the road the whining get quite. Cant fig it out.. Shifts great no issues in shifting

I am sorry to say that noises are difficult to analyze from the perspective of a computer -- so you'll have to have an experienced technician near you have a listen for themselves and give you advice. Most will do that without any kind of a charge - to listen and give diagnostic suggestion. Not a diagnostic test, but some assistance in what to do next. It does sound like something transmission related if it changes depending on gear selection.