I have a m80 diff with 3.9s new lsd shimmes and bearings out of a bf wagon in my au ute it's all in and drives except there a really bad whine when I accelerate other then the diff been buggered could it be the tail shaft stuck to far into the gear box as the diff is slightly bigger in diameter, the tail shaft yoke going into the gearbox is butt right up to the gear box is there meant to be a bit of the tail shaft sticking out of the tea of the gear box for play when driving if that makes sense ?

From my understanding there's meant tone about a 20 mm gap between the gearbox and the dampener on the yoke

This would be a really good opportunity for a photo...

There should be space for the tail shaft to go into the diff... As the back wheels come up the tail shaft will push into the gearbox further to a point where the diff yoke is inline with the tail shaft yoke anyway...

Cheers,
Tim

Sweet guys looks like I've got about 20 to 30 mm gap, so this means something's wrong with my diff then. it whines really bad under load 4th and 5th is ear pearcing( don't trust what u buy of gumtree kids)!!