I've got an uprated LSD in an Escort RST gearbox on my shed.

It's been pulling to the left and right a bit ever since it was fitted, but in the last couple of hundred miles it's become almost undriveable - it's pretty much changing lanes all by itself and it feels like it wants to oversteer through every corner.

I just jacked the front wheels up one at a time and tried turning each wheel by hand with the other side on the ground and it's almost impossible to move the wheel. It's smooth - no notchiness or snatching - but much much harder to turn than I remember it being when new.

Is this a sign the diff's not too well?

/al