Testing limited slip differentials

Just jack up one rear wheel and leave the other on the ground. It should be very hard or impossible to turn the wheel by hand. LSD's do wear out and if you can turn the wheel fairly easily, then yours is.
Cheers

Just thought I would practise what I preached, never having actually tested it my-self.

So I jacked the rear right tyre off the ground leaving the rear left tyre firmly on the pavement, put transmission in neutral with the handbrake off.

The Traction Loc LSD I have should need around 28 Ft/Lbs to overcome the Culches in the diff, So it was out with the Toque wrench set to 28Ft/Lbs and placed it on a wheel Lug nut on the right rear and tried to rotate the tyre sure enough the Toque wrench clicked at 28Ft/Lbs just before the right tyre over came the LSD clutch plates.

Fisho is correct, there has to be some torque on the lifted wheel to operate so put some friction on the spinning wheel and you will find that if the LSD is working then it will try to move fwd on the trolley jack.
In a situation in very slippery conditions it helps to have a notch or two on the hand brake to lock up the lsd so that some traction can be gained on both wheels, this only works when the handbrake is on the wheels not on the drive shaft as in a Nissan.

I assume you were referring to my reply

A LSD is Limited in that it will allow limited slip between the wheels to a point.

A LSD will slip if one tire has no traction and the torque input coming down the driveshaft and the traction of the tires combined is more than the clutches can handle, it will go back to operating like an open differential and send the power to the wheel with the less traction.

This is essentially what you are testing by having one wheel off the ground and the other firmly on the ground and rotating the wheel that is in the air, the toque wrench set to the correct Factory Setting is measuring how much force is needed to overcome the culches in the LSD.

Unless it's a Torsen Diff like the NM/NP Pajero where you must have some grip on both wheels for the diff to function. If one wheel has no grip at all it will, apparently, act like an open diff. Once the diff starts to bite, however, it will just keep gripping. There are NO clutches in a Torsen diff.

See Torsen diffs

Peter

I have been told to ensure the LSD is working to drive it in 5 full left hand turns and then 5 right hand turns, this is to allow oil to get into the cluch system to check the LSD, also have tried the jack on one wheel, didn't move at all, stilll not sure if my LSD works.

exploder, dont know why but I actually hadnt read yours! But you are totally correct!