Yesterday when I was putting my 2003 envoy into park I pressed a lot harder than normal. this resulted in the release button you press with your left thumb to unlock the shifter so you can shift into a different gear becoming stuck. I took the boot off and looked down and noticed that the small piece that moves up and down when you press the button to either locks it into the set of gears or unlocks it so you can move to P>d321>R . I can see a small spring underneath but I am nto sure completely how the system works.

before I go taking it apart I was wondering if anyone could offer some suggestions or help.

at the moment the shift button is stuck in. so it can freely move to any gear without locking. which isnt too safe seeing how i park on a hill