Auto transmission wont lock in P

[chas3FD]

I noticed a problem with my truck, if the wheel drive selector is set to "Auto," the transmission wont lock in Park, and the vehicle can roll freely. It caught me off guard the first time i tried to leave it, and now i'm trying to figure out why this happens and if there's a safe way to prevent it.

 

[BoostedAndConfused]

I think there might be a problem with the transfer case linkage that's impacting how the park pawl engages. I'd make sure to use the parking brake at all times and have it checked out as soon as you can. This could be a safety concern since the transmission might not be fully engaging in park.