2003 monte carlo whining noise and hard shifts

Transmission. Check fluid level using proper checking procedure, which is usually get to operating temperature (take it for a short drive), park it in neutral idling, parking brake on. Fluid should be at correct level, and red in color. Anything else, have a transmission flush and fill, do the filter as well, just to be safe. It's a good place to start. And hopefully you don;t have bigger problems. Hope this helps.