extended use of treadmill=changed mechanics?

Does anybody else find running on a treadmill awkward? I can’t get any rythm in my running, or at least not for any extended period of time.
Every step feels like something is missing, and of course something is missing, and I don’t like the idea of getting used to it.
Could running on a treadmill for extended periods change your mechanics?

I feel okay while on the treadmill. Once I get off though it’s another story. I don’t risk using a treadmill, because with some of it’s potential drawbacks, there are a wide array of other options out there that can be used for low intensity work.