Truck Shifts freely after Changing ignition tumbler

[Pooble]

Hey  guys this is my first time posting on the forums, recently bought a 2003 gmc 2500 6.0 gas. 4x4

So last owner got stuck in his driveway and had bypassed the mechanism by breaking the tumbler & started the truck via the ignition switch (already checked if it was stolen lol). i think he played with a few wires to bypass the security as well, but im not to sure on wiring.

So to the point i had to drill out the old cylinder and play with it cause it was jammed and could not set it to the ignition setting to pull the old one, during this process i noticed a cable came loose that connects to the cylinder housing and would move with the key when you go from power to start it, pulled it out by accident & then truck was locked in the park position after i put the cable back i was able to shift but noticed it shifting freely afterwards. Already put a new tumbler in but still can shift with no brake, even with the truck off. I can still pull that cable out and the truck will lock into park but when i put it back it shifts free again.  

 

I just took the truck in for an out of province inspection(canada), and that was not an issue at the time so im 95% sure i did something to cause this. but could also have not noticed it as its second nature to put your foot on the brake then shift. but doubt it as it was just inspected yesterday

Any help is appreciated and i can also post pictures when i make it out to the shop. Thanks!! ( Just remembered as well, disconnected the battery prior to working on the tumbler. because i was checking horn wires under the airbag, as the horn does not work not sure if disconnecting&reconnecting the battery can affect shifting in anyway)    

Edited December 19, 2018 by Pooble

[sefiroxx]

The cable is manually linked to the locking mechanism farther down the steering column. Yes, the cylinder, when turned, engages the cable end and moves it allowing for lock release. Turning the cylinder back returns the cable to the locked position.

Follow standard procedure for installing the cylinder (from the run/start position) and make sure the cable is positioned to the unlocked position before installing the cylinder.

[Pooble]

Thank you for the clearing that up wasn't sure, was also doing some research i guess its normal for some GM shifters to move without your foot on the brake for safety reason such as emergency crew being able to move your vehicle in an accident? is this true and or a normal thing in anyway. Thanks again