<VV> old pinion gear on new shaft?

[John McMahon]

Hi, everyone.  I have a problem.  My pinion gear is slightly loose on the 
shaft.  About .005" play in-and-out and side-to-side.  I was able to remove 
the gear with a gear puller, which may be indicative of how loose it was. 
Anyway, I'd like to know if it is the norm to be able to install an old gear 
on a new shaft, or if you have to use both a new gear and a new shaft.  It 
seems to me that the gear would be made of harder metal than the shaft and 
thus the wear would be on the shaft, but I don't know.  There is no wear 
than I can see or feel, but obviously it's there.  Any advice appreciated!

Thanks,

John McMahon
1965 Monza coupe w/ 4 speed (and 3.55 diff, if that makes a diff)