Australian Car Repair Issues? Ask an Auto Mechanic for Answers ASAP
The faults you're throwing make it sound like it has no fluid in the tranny- I'm assuming you have looked underneath to make sure someone didn't hit something and "let the fluid out"?
Also, check the wiring harness connectors to see if they are seeping fluid through the pins- I have seen this happen, and it can short sensor circuits together, causing errant readings. You may be able in this case to get by, at least temporarily, by cleaning out the connector and housing with some brake parts cleaner to clean up the fluid and stop the short, until you can replace the wiring harness.