That motor you hear running is the Accessory motor and normally times out if you are not using steering, reach or side shift.
Confirm first your battery is fully charged, then make sure the park brake releases.
A dirty or burnt normally closed directional contactor tip will throw a 48 fault and you will notice no contactor click when operating handle.
Sometimes tapping the contactor assembly will jar the tips and unit will run.
Also inspect your drive motor brushes, a worn or open brush set will also display 48 with no directional function.

Sounds like your forward and reverse contractors need refurbished. I would start there.