Driveshaft installation

If you gently clean the output shaft on the transfer case and the input yoke on the differential there should be yellow paint dots. The new shaft should also have (usually yellow) paint dots. Line those up at both ends and that is it.
Be sure to use blue loctite on the bolts on the carrier and rear flange and tighten the flange bolts using a cross pattern so it seats fully and square.

That makes sense. I'm only doing the rear shaft. So basically the O.E. front shaft will stay and not be removed. Only from the carrier back is what's being replaced. So should there be marks as far as where it bolts to the rear differential?

If you bought the complete shaft it will go from the transfer case to the rear axle as the carrier bearing is part of the front section of the shaft as shown in the image. The two piece shaft has to be replaced as a unit to stay balanced.

Okay. So the "rear" does go from the transfer case to the rear differential?

Yes. It goes from the T-Case back to the carrier mount, then the rear section goes from the carrier area back to the rear differential flange. The whole thing is balanced as a unit.

How much fluid will need to be replaced?

With it not running you shouldn't lose any, the front yoke into the T-Case is above the fluid level and the rear yoke doesn't come off for the shaft to be replaced. Oh, If you noticed the image shows the wrong transmission, but the 4X4 works the same way. Depending on which case is in it you may have a front bolt on joint and not a slip yoke, Ford used both depending on which case design and which wheelbase and options you have.

It is the slip yoke. It slides into the transfer case in the front. Bolts in the middle on the center support bearing. Then the 4 bolts in the back on the rear differential. To me it looks like everything else puzzles together. I'm just not sure on the whole "marks" with the new drive shaft. Or doesn't matter? As long as it slides in it should be good right?

In theory a new shaft should be balanced and ready to go. The marks are there just to eliminate any issues. Having the slip yoke version is a little easier, you don't need to hold the shaft in place to line things up, it just slides into the case. I would recommend changing out the seal in the case though, just to prevent any leaks. They can take a set from running on the yoke for a while and then don't seal as well on the replacement, they are a simple pry out and tap in design.

Awesome. Thank you so much!

You're welcome.

What gear should it be in for the install? Park or neutral?

Depends on how you are getting under it. On a lift I leave them in park because I can rotate a tire to move the driveshaft to line up bolt holes, if I'm doing it on ramps or on the ground I put it in neutral so I can rotate the output shaft to line them up.