Renault Megane 2008 Problems

As everyone is in furious agreement that the diff is noisy it would seem you would have a good case to claim against Renault for a new diff and I would pursue that course.

Now that it's out of warranty I would suggest you seek out a Renault service specialist and talk to them about it. It sounds as though it could be going lean when you give it a sudden burst of throttle. I would be cleaning the throttle body.