First off Sprint and Google Voice are more tightly integrated than other carriers. Depending on how you had it set up you may never be able to duplicate it on TM. I don't recognize that **416 feature code--it's not native cdma or gsm--may be unique to the Sprint/GV partnership. GSM uses *67 for fwd if busy, *61 for fwd no answer and *62 for fwd if unreachable. Easy way is to go to phone app, menu, call settings, call forwarding, voice call. Should query the system and show you what's currently set. You can change each setting there also. There are some APPS on Play Store that allow fast changes once they're configured. Depending on your Sprint/GV setup you may have to somehow reset GV to not expect Sprint.