its located at the rear drive axle
take the axle out
Open the drivers door and look for an information sticker on the end of the door It will have the axle code for your truck
Speed Sensor The sensor is located on the rear axle housing.
Mine is 3:55
What type of rear end do you have?
I believe you can find the axle code on one of the stickers on the end of the drivers door - then the code is used to find out what differential gearing your F150 has
About 1.25 liters of oil goes in the rear axle of a Ford transit. It takes 75W90 oil when you replace it.
I believe axle code " 18 " is a 3.08 conventional axle ( non limited slip )
I have done it myself twice now and the second time I wanted to make sure I remembered everything this is the best web site for step by step instructions... http://f150online.com/forums/2004-2008-f-150/290828-how-replace-rear-axle-seals-bearings-your-04-f150-lots-pics.html
there should be an axle code or the door jam. Then you can call your local ford dealer and the can tell you, but some of the owner manuals had a list of the axle codes in them.
you will have to have the axle pulled at a shop.the bearing slides along the axle shaft and seats in the axle housing.