On the assembly, the spring rides in a cup to keep it out of the bearing, and centered in the hub. I have never tried using D44 springs, but if you do, make sure it will turn with the hub, and wont gaul on the spindle nuts.
Have you tried getting them from a Spicer Dealer. If you PM me I will give you a # who can get all the hard to find spicer parts.
88 4.0, np435, atlas, d44's arb, on 37