Trem bar noise is typically one of three things,
1. There is no grease left on the tip of the bar [or the shaft if you like a bar with
loose bushings] and the lock spring is squeaking in it's detent. Put a little grease in
the detent on the bar, insert, and spin it around a few times.
2. It's not the bar but the arm holder which is loose. It has a tendency to squeak
quite loud when it turns. Easy to check by watching the arm holder while you
spin the bar.
3. The spring that holds the bar in the holder is cocked sideways or
otherwise jammed at the wrong angle. Sometimes just loosening the spring screw
and re-positioning it will clear the noise. Other times if it's bent you'll need
to remove it and bend it so that the tip enters the holder straight on.