/I have a new sound I could use some help decoding on my '71.  It's a 
/subtle high pitched (whistle like) sound that doesn't appear to be 
/directly related to wheel speed.  It occurs in all gears (well, I'm sure of
/2-4, but the engine revs in 1st might drown it out) but does go away 
/when I press the clutch in at least half way.

I know this may sound odd, but how clean is your engine compartment? I have a
72 (suitcase type) but this could apply to either
the upright or the pancake.  I live in a suitably wooded area, and while
I go to some lengths to park away from piles of leaves (left over from a
lazy daughter) occasionally I find I've sucked a few down the fresh-air
ducts on the rear of the Bus.  Generally, this has little effect as they may
swirl around for a bit until I scoop them out, but there was once a time when
I tore an engine out of the bus and had it most ways apart before
I found the source of my mysterious whistle.
Seems a stiff Oak leaf had gotten lodged against the fan shroud and the
cylinder fins. The effect was similiar to the noise one gets when you cup a
grass leaf between your thumbs and blow (Indian Whistle!) hard.
Also, the noise increased and decreased depending on engine speed which made
it doubly hard to diagnose.
While this type of critter wouldn't go away when your clutch is semi-
depressed, perhaps it will point out there are a few odder options you may
check!

Good luck

Kevin Murray  -FEETSFirst Films

1965 SingleCab  (FS 3000.00 obo)
1967 Panel Bus  (FS   400.00  obo)
1969 Beetle
1969 Beetle
1972 Busto-Westie
1974 412 Station Wagon
1976 Rabbit LS (FS   300.00 obo)