[bishopts]

Lift the rear wheels off the ground on stands,
start the engine,
take off the parking brake,
turn off traction control,
FULLY press the clutch and put it in first.
See if the wheels start turning even though you are still holding the clutch. With full clutch disengagement you might still have slight movement from the pilot bearing turning the input shaft, it will look like a partial creep in the wheels.
But if your clutch isn't fully disconnecting then you're going to see the rear tires rolling enough to see it in the speedometer.