This is my first post, so bear with me. I'm coming due for my first oil change (600 mile). I know, not another oil question! I'm going to use Amsoil 10W40, the new and improved MCF. The Amsoil dealer told me that I can use the 10W40 motor oil in the rear final drive. If the oil is good for the engine and transmission, I figure he may be right. I just wanted to see what others have heard. Thanks in advance for the comments.