It was less than 3/4"...and that axleshaft was replaced about 8 months ago, and I made sure that the C-clip was on there good, so I highly doubt that it came off.

I got two sets of bolts from Kragen; both the right diameter and thread pitch, but one's slightly shorter than the original, and one's slightly longer...I would assume that one of the two will fit. Both sets are stamped as M10.9, which IIRC is the metric equivelant to a Grade 8...

Also, I'm almost afraid to ask this but is a little bit of play in the axleshaft (between the CV joints, with no movement of the "jugs" on either end) normal? I can move the driver's side axleshaft towards the differential and back maybe 3/8"...not nearly as bad as the old one, which could move a full inch, and the boot still seems okay...