I was told from another Ford service representative not to put the XL-18 . the dealership said it is a ford motorcraft product so it would not Void my warranty, but by that reasoning I can put motorcraft 5w30 in my transmission for the warranty so don't believe a word they say. this is very frustrating that a large company doesn't know what fluid put in its vehicles. do I add the additive or not I have no idea...Chart says yes but no one at dealership and some reps at Ford have never heard of it...and now chart has changed. I want to add it but also want a warranty. Very very frustrating and disappointing...and confusing.