Sometimes, you might be able to resolve some of the issues using Output Interpreter.You can paste output of sh techsupport into OI to do this. Cisco TAC might have some internal tool which can take a look into a stack trace (part of sh tech support) and decode the information, as to why a crash of a router happened (or a hardware failure etc)..
Sankar Nair
UC Solutions Architect
Pacific Northwest | CDW
CCIE Collaboration #17135 Emeritus