Good diagnosis !!No worries this just happened to me and I thought that my transmission was missing up and that was not the case Thank God! When this happens all you need to due is pop the hood and place you crank shift back on the screw knob and it will move into gear! You must change the part that’s inside your crank shift or put some adhesive on there to seal it from coming off again! Keep in my, if you do place the crankshaft back on and the plastic rim that’s in the middle doesn’t latch on, be careful because once your in reverse, you can’t put your car into park, neutral, or drive and if you are by yourself you are going to want to keep your foot on the brake and also lift your emergency brake and call for help! Again this happened to me 3 weeks ago and after overnight YouTube’s and google I was able to fix the issue and saved me thousand of dollars!
I've had to replace the end of the shifter cable on one of my Cruzes, but never would have made the connection between that and thomas2000's description. Now that I see them together, it makes sense.
BTW, here's the GM part number for the shifter cable end (aka adjuster) that I purchased: 22847616 . It was around 3 or 4 dollars at my dealer.
BTW2, for anyone curious, the cable end is a plastic sleeve around 3" long that has a grommet in one end that fits on the shifter crank on the transaxle. The shifter cable attaches to the other end of the plastic sleeve. The grommet can deteriorate and fall away resulting in a very loose connection at the crank causing sloppy operation of the shifter.
Very important: Before removing the plastic clip holding the cable end to the cable, make sure the position is marked on the exposed cable so that the new cable end goes on in the same spot.