It could be dozens of things, but a transmission specialist should be able to diagnose it quickly. This is an older, well-known car and there’s not much a good Mitsubishi mechanic won’t be able to assess accurately.

But before you call a tow-truck, check the level of fluid in the transmission via the dipstick. If there’s no – or low – oil, you might have figured out why the vehicle won’t move. The job then becomes one of working out where the transmission fluid went, because these are sealed systems and shouldn’t need topping up between transmission services.

It's very hard to put a value on old cars like your father's. An average Magna of that age is usually worn out and worth next to nothing, but your father's being a low-mileage example in good condition might make $2500.

THE Civic is generally a reliable and well-built car that should be cheap to run. As far as your trade-in goes I would think you would be offered about $2500 for the Magna.