Isuzu D-Max 2013: Is it a lemon?

It’s clearly frustrating you, but I don’t believe you’ve copped a lemon on the basis of what’s happened. Isuzu fixed the diff, end of story, they also replaced the first pump under warranty, again end of story. The issue is why have two pumps failed, and why didn’t Isuzu cover the second pump. These are questions I would be putting to Isuzu. I’m guessing that the second pump wasn’t covered because the warranty had expired after three years.