I had a problem about a year ago with my rear shaft it leaked gear oil on 2003 Mercury Grand Marquis

now its doing the same thing when I drive and it go to change gears its make a sound of ramble (not sure how to discribe). and I want to know how do I add gear oil, my husband used to add it under the rear axel is this the correct spot

Asked by for the 2003 Mercury Grand Marquis