2003 Chevy Trailblazer diffrential leak

Transmission problem
2003 Chevy Trailblazer 6 cyl Four Wheel Drive Automatic 84k miles

Hello, my 2003 trailblazer has a front end (left) diffretial leak it seems that a lot of people have the same problem is this something worth fixing or just keep adding fluid, because it seems that if you fix the leak it could open up a lot more problems. If you think it should be fixed how difficult and how long, I will by the book but just looking for some insite. If it is to hard then maybe I will sell it. Any one in the new york area that can fix this problem please make contact. Thanks, Greg