It seem that the winch bracket makes it impossible to to remove the fill plug on the front diff. so I called the dealer to see if they had this problem with the newer 500s with the winch installed. They told me that they use the diff. vent hose and pour the demand drive fluid down this hose to fill the diff. So that is what I did. You have to remove the radiator panel under the front storage box cover and find the vent hose and pull it out and tape a funnel on the end and pour the fluid in real slow. This is far easier than removing the winch bracket to get at the fill plug.