After replacing my steering rack, the steering wheel while in pafrk shakes violently back and forth

[B Nemitz]

    Today I replaced my steering rack on my 06 4x4 pathfinder LE. Now when I start the engine while in park, the steering wheel will start to shake back and forth violently even after I try to slowly turn the wheel back and forth in an attempt to purge the system. I mean VIOLENTLY. Can anyone help me trouble shoot and diagnose why this is happening? Is it possible there are either small plastic stoppers or some type of cap to protect the inside of the the part that I didnt see? Is it possible the metal lines aren't seated correctly even though I took care to make sure they were? The vehicle is on a slight hill with the front facing up. Is it possible air is in the system or it needs to be on level ground? Or something else I didnt consider because Im not a pro like many of you are? Please help me and thank you all very much in advance.

[Trevor]

I believe it is air in the system which you can clear by turning the wheel from lock to lock