An update for
@Cardy George on the Monaro.
We stripped three diffs today. Two at 2.78:1, one from a HZ which has a smaller universal yoke and the factory original 3.36:1. The 3.36 is a lost cause and the HZ 2.78s is very good, the other 2.78 has badly chipped planetary or sun gears and the star or side gears aren't much better. The bearings were spotted and overall not a pretty sight.
Plenty on the interwebs saying that the taller ratio Salisburys wont accept the lower ratio gear sets and that the sun gears and side gears are different. The explanation was that the taller ratio had a smaller centre to accomodate the smaller diameter crown wheel. So this applies to the 2.6 and 2.78 which share a centre and the 3.08, 3.36, 3.55 and 4.44 share a different centre. Makes sense.
Well sort of. The crown wheels are the same diameter and same pcd but have a different number and form of teeth with the taller crown wheel having two extra teeth! The pinions are significantly different with the taller ratio pinion with a larger tooth count and physically much larger. The centres are the same size except the mounting flange for the crown wheel is offset about 10 or 12mm to allow for the larger pinion! The internal gears and shaft and washers are identical.
So this leaves bil with a couple of options. Rebuild the good 2.78 with new bearings and throw that into the best housing, shim it to suit and run that or clean up the 3.36 centre and run that with the good star and side gears and obtain a new crown wheel and pinion. So now it is dependent on the 3.36 centre clean up. If ok he will go the latter route otherwise the 2.78 will go back in and we sniff around for a 3.36 diff.
I did have a lead on a 3.36 and was supposed to look at it today but the person selling it has obviously accepted a better offer as the ad has disappeared. He didn't even bother to tell me it is sold. Scumtree is such a great thing.