Appears to be working just fine, but make sure the clutch fork is returning all the way back when the pedal is released. Can you push the fork manually back toward the rear of the car with the pedal released. Even an eighth of an inch can cause slippage. It's highly unusual for a clutch to give out in 4000 miles but I guess a spring or two could have failed. Is there any
oil seeping from the bell housing? Leaking seals have been known to coat a disc at times though very rarely.
Looks like you're going to have to pull the trans and check the pressure plate next.