overdrive Transmission

I was wondering (forgive my stupidity but i have alot if it) what the overdrive is on my 2001 grand prix 3.8/ n/c engine. Someone said maybee its not shifting into overdrive how do i found out am i looking for a ligt that says overdrive or is it supposed to be at a certain rmp level at a certain speed before i fell the car shift is so can someone please tell me at what speed or rpms the car should be at as it is shifting through the gears. thanks

Once you hit 50mph and let off the gas,the transmission should drop into overdrive from about 2000RPM to about a little under 1500RPM on the tachometer. It actually a little over 1300RPM if your checking from a scan tool. It will increase slightly as you aproach 60mph.
You can kinda feel when the torque converter locks up nothing harsh but....you can feel it.