I’m not sure what changed, before I wasn’t able to forward my voicemail from my Tracfone to my Google Voice account, but now it just works. I had previously done some research on the web and found that Tracfone doesn’t allow call forwarding which precludes using another voicemail service
So I was playing around in my Google Voice account and for the heck of it decided to see what would happen if I clicked on the “Activate Google voicemail on this phone.” At one point I know Tracfone was using T-Mobile in my area, so I had tried using the T-Mobile settings to forward voicemail, but Tracfone must have changed to AT&T, because I tried using the AT&T instructions and it just worked.
Initially I tried calling my cell from my land line to test the voicemail switch, but for some reason instead of getting a greeting I went straight into the voicemail backend, you know the “you have X new messages” part. It turns out that I have direct access to Google Voice enabled on my land line, so it was going through some sort of causality loop. I temporarily un-enabled GV on my land line and called my cell again — this time I was greeted by my on cheery voice telling me to leave a message. Unfortunately (or fortunately) this means if my wife calls my cell phone from our land line she can’t leave a message, but I’ll still get a missed call notification