Handedness of Replacement Halfshafts?

[Bob Culver]

For other makes which fail at splines it is considered very poor practice to reverse a half shaft. Often leads to early failure. Occassional early overstrains considerable increase resitance to fatigue in that direction. But when crack tested Seven axles often reveal a crack at the corner of the keyway on the drive side. Often seem to progress initially and very slowly around the semi circle cutout rather than across the axle. So probably better to fit reversed! (And as previous it is important that full or at least good contact is made inboard of the key so the key section of the axle transmits minimum torque and bending)
I would not worry about meshing of the gears. On other makes with mitre gears these get into a parlous state with no effct other than harmless increased backlash.