yeah does sound like the main shaft bearing has given out.
its a weak point mate, my gearbox decided trho $hit it self years ago, had no warning, it just sounded real crap when i went home from a mates, by the time i got home it wouldnt even reverse! once stripped , main shaft was fooked, 2nd in input shaft had5 full teeth left, and the magnic wasw about a inch thick,

live and learn.