Here's Boomer (1980–1982)

I adored this show when I was a little kid. Contrary to the review by "Robert Morgan", I recall that Boomer didn't look anything like Benji, but was actually a rather large, shaggy mongrel. I clearly remember an intro/opening credits with this large dog placing mail in a mailbox and raising the red "collect" flag on the side, and a Benji sized dog couldn't do that. I was 6 years old when the show was on though, so it's possible I've forgotten.

This show did borrow the premise of Benji (which I also loved), involving a very bright dog who goes around helping people. It capitalized on the popularity of "smarter than the average dog" shows, and was great for parents to watch with their children, to learn about compassion and humanize animals a little bit, hopefully teaching children that animals deserve our respect and love.