I do agree that removing the axle smoothly and installing it smoothly requires everything to be ligned up nicely (backing plate, spring, etc.) i am fortunate to have a laser system for squaring the rear end, when I laser a car i shoot both rear wheels, then I roll the rear wheels 180 degrees and laser it again, if the numbers change I can tell if a wheel or axle is tweaked. Also if the number are off I can tell if the housing is jacked. Never fails if the housing show tweaked, when I remove the axles it is a fight. When I reassemble with straight stuff its smooth sailing. I will tell you guys, I am a dealer and NEVER used USLC housings until recently. I am now comfortable with the housings and the new jig process, they laser staright and the numbers are good. Like I said a little tap to seat the axles is fine, if you have to force the issue you have areal problem.