Gearbox had developed a whine which I took to be diff bearings. Replaced the bearings with gearbox in situ but now cant get RH half shaft back in. No obvious problem so took gearbox out and stripped the diff out, Seems to be something awry with the gear that the half shaft goes into, tried the half shaft on the side of the diff went in no problems Tried the gear on the other half shaft, cant get it on other than a few mms Tried both shafts on an old  non lsd diff and both went in no problem   Gear seems like its gone oval,out of shape or tight, cant see any issues with the splines. Tried alternative positions but no go. Anyone come across this before?