My S80 drove perfectly yesterday as always, got me home with no sign of trouble at all.

Today I didn't even make it out my driveway and a loud clunking noise appeared, along with the tracs light that comes and goes. I really don't understand how it happened so suddenly, working fine yesterday, being parked up overnight and it appears within about 3 seconds of driving this morning. It sounds like its coming from the front passenger side (drivers side for people in the US) where the gearbox is. I jacked up the car but all the rubber gators look fine around the CV's etc and there's no oil or anything on the ground, could it be the gearbox? The noise happens in a straight line, around corners, going forwards or going backwards, but doesn't happen when creeping, only with light acceleration and at slow constant speeds. I haven't tried going faster than about 10 kph. I heard these gearboxes are prone to issues (I don't know what issues) but this one doesn't even have 90,000 km on the clock yet (56k miles), does this sound like a major issue or a minor one? Video attached.

p.s, the engine light has been on for two years, I don't think this has anything to do with this. But that's another problem for another day.

Thanks!!