Gear shifting problem

Welcome to 2CarPros.

First, I am basing the information on a Montero, which is the name of this vehicle in the US. Also, I don't know if your vehicle is 4wd or not.

The first thing that comes to mind when you say it will reverse when you place it in drive is either the range sensor or the shift cable has come loose and is no longer moving the shift lever on the transmission. Since it isn't selecting the correct gear, I have a feeling it is loose at the sensor. See picture 1.

Next, I attached three more pics. The show the shift cable and where it attaches. Please check those areas to confirm the cable is not loose, damaged, or disconnected.

Let me know what you find,

Joe