KenmoreGal2,
Well, I don't know about replacing it every year. I have several owners manuals for machines with that type of gear box and not one of them says to replace the grease on a regular schedule.
Miriam has a saying that you shouldn't let your machines know you are in a hurry. So order the Tri-Flow grease from Sew-Classic, and you'll have it when next you need it.
You can always fill the pocket with one of the greases you have and use it till the T-F arrives.
Joe