1993 240SX with 5 speed.  Had my trans "rebuilt" about 4 months ago
since I was having issues shifting.  Since then, I've had a
vibration/rattling problem that they can't seem to get fixed.  Sounds
strange..but when I'm sitting at a light with my foot off the clutch,
there's a rattling noise coming from the front of the transmission.
Push down on the clutch and it goes away.  The rattling gets louder as
the car heats up...you can't hear it for the first 15 minutes or so of
driving.  Also, turn the headlights off or step off the brake, the
rattling dies down a bit (almost like the car is idling faster without
the lights on so the rattle goes away).  I know it sounds strange but
I've been dealing with it for 4 months and those are the symptoms.
The transmission place has had my car for 6 weeks over the last 4
months "fixing" it and everytime I get it back, the car heats up and
the problem is still there.   Anyone have a clue what I can tell these
guys to look at?