it is posible,
save the file of the route,
be sure that you have the garmin app on your phone
Garmin drive app
go to the folder where your file is and open the .GPX file.
it wil open direct the Garmin app or els it wil ask you what to do.
open the Garmin drive app and the file wil be transported to your Garmin nav.
if it's not working, your Garmin is possible to old fot this.