When I shift into first, second or drive the transmission is missing the slot

Welcome to 2CarPros.

Is the transmission shifting properly when driving and the shift lever the only concern? If it is shifting normally, chances are the transmission is fine. Most likely, the problem is in the shift lever. I attached two pics below and circled specific parts. The first shows the shifter arm and the cable. Toward the bottom of the shifter, there is a roller type bearing that sits on a channeled mount. If the roller has broken, you will feel little to no resistance when shifting and it will feel like nothing is actually happening. What I mean is, you won't feel a slight bump into a selected gear through your hand.

The second picture is the roller and mount I am referring to. You need to remove the shift panel and inspect that first. I suspect that is the issue but can't be sure until it's checked.

Let me know what you find or if you have other questions.

Take care,
Joe