[FuLL BLown STD]

my buddys 88 si civic has always been a problem free car until today..when all the sudden he couldnt get the car into reverse..and when he put a tad bit of muscle into it u would feel a grinding..like something was spinning and grinding lol and then suddenly he tried reverse again and i heard this loud thump..the car instantly stalled and now it seems as if reverse is totally locked out..could this really be the prob or could there be something less serious going on.. can reverse bee fixed easily or should he just go out and buy a new tranny or what? no problems 1-5..smooth shifts. thanks guys n gals