sorry i dont quite understand.. so your saying my diff internals might be damaged?? can you find a definate answer by checking something else.. so did you just weld something inside the diff to fix it?

my guess is that the shaft that runs throught the spider gears, into the diff centre is damaged, becomes elongated. feels like the diff has HUGE backlash? i had this prob with a mates Ke70 corolla... i just welded the elongated part up.

ok i had it up on the ramps yesterday and had a go at twisting the tailshaft the opposite way i was trying to turn the diff side of the uni.. couldnt move it the slightest.. ok i could but i could hardly see the movement..well less than a mm prolly a quarter.. it was just enough to feel..

thanks bert.. ill give it ago this arve.. and i spose its pretty crucial to have it tight.. prolly only take 1 unlucky dump of the clutch and snap..

Jack the car up,PUT IT ON STANDS,out of gear,get under the thing and grab the diff pinion yoke(where the tailshaft bolts)with one hand and grab the tailshaft with your other hand twisting in opposite directions in a circular direction plus up and down.If there is any more than about 1mm of movement(none is best)it's time for new ones.
Do the same thing at the front,but knock it into gear to stop the gearbox turning,90%of the time the front will be ok.
Enjoy

so if i look at the uni it will be loose?? i got my mate to look under yesterday and i put it in reverse and let the clutch out till it bit then put it in first till it bit.. and he said there was a fair bit of "play" in the tailshaft-diff movement..

My money is also on the back uni,$120 for this work is cheap,as they will have to cut the tail off the tail shaft and re weld a new(servicable) end back on,balance the new shaft and re fit it.Average price for this work on the Goldie is normally around $220 plus remove and re install if you don't do it yourself.

These genuine Datsun tailshafts where in my opinion Nissans biggest engineering cock up using non servicable uni's.
Glad they got everything else right.

Let us know if you don't know how to check it yourself.
Cheers

Best you get under the car and have a look, you shouldnt have too much trouble telling if its a uni or not if its as noisy as you say.

Rockhampton, QLD.. i called 2 places yesterday and gave up.. they said its most likely my uni joint which is $120 drive away but it could be something else..

where abouts are you i have a few spare tailshafts and diffs for 120y's in sydney
if needed