I bought a new D22 in April. From the start had problems with diff. Grinding, clicking noises and clear resistance. It was especially evident when reverse parking and turning in those tight MEL concrete car parks. Took it to Nissan and had the diff replaced the same day, no questions asked. And no paperowork to document it either... lol.
Didn't get any answers to my questions on what the problem was, they said they didn't look, just replaced the diff. Make out of it what you will, but it seems that there is a definite problem with the D22 rear diff and Nissan wants to keep it low profile.