What am I doing wrong?

[GregWeld]

Assuming you're running a Ford 9"?

I've had to trim axles too... best done with a "chop saw" style saw and an abrasive disc.

Dan -- put some kind of witness mark (I use a magnetic dial indicator) on one side of the axle and housing - then tighten the opposite side - see if the axle on the witness side moves... if so they're touching in the center. They need about half an inch in clearance.

This binding issue is bothering me... and it isn't right, so something other than a bandaid needs to happen to figure it out.