Diff Whine and options to fix

[nustad]

Howdy all,

I have a 1972 240z and the diff whines like hell from 45 to 65 mph which I am assuming is wear in the gear set rather than bearings. The car has 90k original miles from what I can tell.

Any thoughts - I don't see many people posting about diff noise.

I have a spare diff out of a 72 240 - is there anyway of assessing its condition without doing a full tear down?

I also have a couple of R-200 diffs but not the 280z moustache bar so will probably leave those for now. In New Zealand getting a 280z moustache bar is a mission.

Just out of interest does anyone know what ratio a diff out of a 280zx with the L20a motor would be?

Cheers

Glenn

[2ManyZs]

Pulling the rear cover and looking at the ring gear teeth for grooves, chunks out of it, and turning it to check for excessive play will tell you quite a bit.