How does it feel to turn by hand? If teeth not contacting at ends or running on a wear step( blueing OK) and some backlash should be reasonable.
Is the roughness at tooth contact frequency? I dunno what happens if the a.c side gears are fitted reversed. Mention recently of wrong sized axle shaft for side bushes. (I don’t know if this applies to long shaft models, but perhaps may lead to noises from the planet gears).

Location: Auckland, NZ

fill it with a mixture of oil and timesaver and go for a spin.

Kill or cure

Hi Robert,
I've no idea how the axle ran before I took it to bits. The car had only done 100 miles in the last 20 years and was in no fit state for any mileage before being stripped and refettled.

Location: Sheffield

Hi Bob,
Doesn't feel too bad turning by hand - allowing for tightness of all the new oil seals. The crown wheel and pinion also look in pretty good condition - no obvious worn or rough areas. However, although the new half shafts looked to be a good fit - neither noticeably tight nor sloppy - I didn't give them a lot of close attention. So if increasing clearances doesn't effect an improvement maybe I need to look closer in the diff area itself.

Location: Sheffield

Thanks Jim, I'll dig out the Jack French article. Sounds interesting.
Regards
Chris

Location: Sheffield

A universal joint problem possibly most likely. Is the uj somehow causing a loose torque tube ball joint to chatter?
I dont know if long axles were ever thin or now available new, so that may not be a possibilty. Anyway, seem to have covered that.
When pinion is turned by hand, should not or barely feel the individual teeth.

If you obtained a genuinely good mesh pattern that is no mean feat with used parts. Often the wear ridge on the pinion needs to be stoned away. And the fact that the 5.25 diff teeth do not hunt can create two mesh patterns and confusion. But hardly likely to cause the effect described.

Any post assembly adj is usually to try and reduce drone or whine.

Location: Auckland, NZ