When grinding noise replace everything in the iwe system one by one. I fixed an issue and after a week, maybe two, the noise came back. I chose these Doorman vacuum moves and I am very satisfied. It has been 4 months with no noise and smooth operation of 4WD and 2WD. You lose about a liter but it's worth it so you don't have to grind anymore. I would highly recommend them to anyone with recurring issues with iwe.