B757-200 FLT CREW RPTS GENERATOR DRIVE FAILURE AND INABILITY TO START APU CAUSING DIVERSION.

Narrative

CLBING OUT PASSING AROUND 15000 FT GOT AN INTERMITTENT R GENERATOR DRIVE LIGHT THAT EVENTUALLY TURNED TO STEADY ON. COPLT WAS PF AND CONTINUED TO FLY WHILE I GOT THE CHKLIST OUT FOR THE R GENERATOR DRIVE. ONCE THE LIGHT WAS ON STEADY; I PROCEEDED WITH THE CHKLIST AND SHUTDOWN THE R GENERATOR DRIVE. AT THAT POINT I CALLED MAINT AND DISPATCH. I TRIED TO START THE APU. INITIAL START WAS UNSUCCESSFUL. AT THAT POINT; I ASKED FOR ZZZ2; ZZZ1; AND ZZZ WX FROM DISPATCH. THE SECOND APU START WAS ALSO UNSUCCESSFUL. THE FINAL ATTEMPT OF THE APU WAS ALSO UNSUCCESSFUL. BY THAT TIME; WE WERE READY AT A CRUISE ALT OF FL340. ALSO; ZZZ WAS ACTUALLY CLOSER IN POINT OF TIME THAN RETURNING. WE CONSIDERED ZZZ2 BUT WE WERE BOTH UNFAMILIAR WITH ZZZ2; THE WX WAS OVCST AND THE RWY MUCH SHORTER THAN ZZZ. WE CONSIDERED ZZZ1; HOWEVER; WE HAVEN'T BEEN THERE IN A WHILE; BUT MOSTLY BECAUSE WE ALREADY HAD THE ARR INSTALLED IN ZZZ; HAD THE ARR BRIEFED AND WE WERE QUITE BUSY ON THE SHORT FLT TO WANT TO CHANGE OUR PLANS. THE WX AT ZZZ WAS CAVU. I ALSO MADE A CALL TO THE FLT ATTENDANTS IN THE CABIN. OUR DSCNT RATE WAS JUST ABOUT RIGHT FOR ZZZ AND PROBABLY WOULD HAVE TO CIRCLE OR S-TURN FOR ZZZ1. WE DECIDED THAT ZZZ WAS THE PRUDENT CHOICE. WE DECLARED AN EMER WITH ATC AND PROCEEDED ON. APCH AND LNDG WERE UNEVENTFUL IN ZZZ AND WE TAXIED TO THE GATE.