What is the size of a king ranch f150 2002 ford rear axle housing and it is a double cabin

There are 3 different sizes of axles available.(8.8")(9.75")(10.25") Most 2wd are 8.8" but you can get them in a 9.75". Most 4wd are 9.75" although it is possible to get it in a 8.8". And usually the 10.25" is reserved for 7700 series trucks. This is only a rough guideline as vehicles could be ordered with different options or the axle may have been swapped out. If it has 7 bolt rims then it is definitely a 10.25" and if it has 5 bolt rims its either an 8.8" or a 9.75". The easiest way to tell would be to check the axle tag. It should be bolted right on the rear axle housing. This will give you all of the information of the axle(size/ratio). If not you can give your local Ford dealer a call with the VIN# and if their friendly they will tell you.