I checked out that spreader tool you mentioned. That thing is one hell of a tool. You've got to be super careful not to spread more than 0.020" or else you can permanently distort your differential.

I don't have enough room at my house to wrench on this truck, so I took it out to my folk's house in Notus, ID. I called Art (stepdad) and asked him if he'd put the carrier assembly in the freezer. Gear oil in the freezer did not sound kosher to my mom, so Art ran out and bought a Styrofoam cooler and a bunch of ice. He plastic bagged the carrier assembly and put it on ice. It was damn cold putting that carrier in, but it worked.

Those oil seals go in farther than you expect. I took a real good look at the seal he installed on the driver's side last night and it looked a bit cocked. I used a 1-7/8" socket, a hydraulic jack handle and the dust seal tool w/ the critical face removed to make a slide hammer to push in the seals properly. It worked great and the driver's side straightened right out and went in perfect. We put the new oil seal in the freezer for a good hour before installing it. It definitely helped.

Are those white plastic things inside the tubes guides so the axle doesn't mung up the seals?

I just got home and so far no leaks.