2000 Dodge Intrepid starting problems

Hi, I have a 2000 intrepid with the 2.7 litre engine. My problem is when I go to start it all the starter does is make a whirring sound. Keep in mind that the starter was working properly and then stopped engaging the flywheel I believe. I took the starter off tested it myself and it tested allright everything seemed to be working. I then put the same starter back on the car and the same whirring noise with nothing else. I then took the starter off of the car and took it to an auto parts place and had them test it and it tested fine so I even took it back to the place I got it from and had them test it told them the problem and they replaced it with a brand new one. I then put this starter on the car tried to start it and nothing but whirring. I have charged the battery checked the cables to the batteries and done about everything possible to try and get it to crank over when starting but nothing any ideas would help.

thanks
Josh.