Ok guys I have never messed with rear ends. I drive a 2004 Nissan Titan LE 4x4. The other day I was driving about 35mph and the rear end locked up. I pulled over and saw of course the drive shaft hanging down. I took it completely out and put the truck in 4x4 hoping it would get me home (5 more miles) and when I try to go forward in drive the rear locks up. But in reverse it makes no noise and is smooth as can be?? Any help would be great. Tomorrow I am going to slide the axles out and then look at my pinion gears and what not. I don't know a lot about rear ended gears so anything will help me out. Thanks a lot, and this is why I love this site!!!