if your bearings stay on crankshaft when seprating the cases it is the cases, if the bearing stay in cases you may want to check your crank for wear
, $461 for a new set of cases is problably your best bet, will also need to buy new crankbearings as your new ones could be sightly worn if they spun in cases,
also u will probably need a few of your gearbox bearings that could be hard to change ie;clutch arm bearings
maybe a good machine shop could repair ur old cases ,
someone on here could probably recommended where to get it done,[ not sure how good a job it is]