I was just wondering what the diameter of the axle tube is on a front dana 44. Since i needed to get new u bolts to put on my add-a-leafs.

 

Unless you have flipped the u-bolts, your ford uses a square u-bolt that doe not actually go around the axle tube like a round u0boly would. Your only concern is that you buy a replacement u-bolt that fits a three inch wide spring, and are long enough to reach trough the mounting plate under the axle.
Front u-bolts do not capture the axle tube like rear ones do, they actually fit in front and behind the axle tube, if that makes sense.
Take a good look at yours, and you will see exactly what I am talking about.

 

Ok thanks i forgot the u bolts for the front go around the spring.