I have a 2001 F150 Super Crew 5.4 I need to order a replacement front differential 4x4 completely went out and it is making terrible noise while driving I am planning to replace entire front suspension parts so while there I planned to pull old diff out and install new one. How can I tell is it has vacume disconnect and what gear ratio I have in the front.

 

The vacuum line and actuator sit just a bit off center on the passenger side of the front diff. The size is stamped right on the front of the diff case in big numbers. There is a tag on one of the case bolts that gives you the ratio.

 

look at your axle code on the drivers side door sticker

 

Yes, look at the tag on the drivers door jamb. It will look like this one below. This particular truck had an axle code of H9. If the code starts with a letter, it means it has limited slip in the rear.