Date:         Wed, 7 Mar 2007 08:59:47 -0800
Reply-To:     Ben S <phlogiston420@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Ben S <phlogiston420@GMAIL.COM>
Subject:      mysterious intermittent squeek from rear end
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

hi all,
here is a problem that has been perplexing me and my mechanic...
hopefully one of you has experienced something like this before.

a few weeks ago, fred's garage in redwood city, ca installed a new
clutch and rebuilt tranny in my '86 westy.  they seem like a very
competent shope and i enjoyed dealing with them.  my van is primarily
used to shuttle people and gear between san francisco and south lake
tahoe... on her second trip with the new clutch/tranny, i started to
hear an odd rhythmic squeak from the back of the van.  the noise
disappeared as i got closer to home, but i brought it back to the shop
just for peace of mind.  they pulled off the wheels and rear brakes...
checked the wheel bearings, cv joints, brakes, etc and found nothing.
all they could tell me is that i was getting a lot of other noise from
my front control arm bushings which i have put off replacing while i
recover financially from the transmission purchase.

so then last weekend i went up to the mountain again... this time the
noise started in again in earnest and was even louder.  it continued
for three days as i drove back and forth between my cabin and
kirkwood.  on the way home, it became so loud that my sister, driving
her wrx behind me, heard it and thought it was coming from her car.  i
was just about to get worried, when the sound disappeared again.  this
was somewhere around folsom, so i was still over 100 miles from home.
the sound did not occur again during the drive, or during any of my
subsequent short drives.

the roads were dry during my entire return trip so i do not think the
sound ceased due to something drying out.  i was, however, coming down
off a mountain...  so maybe it is temperature related?  barometric
pressure?  i am grabbing at straws here but something, which i doubt
is moisture, caused this dramatic sound to do cease as i drove back to
the city, on two seperate trips.

alright, on to my best description of the actual sound.  it is not too
dissimilar from the noise i hear from my creaking/squeaking front
control arm bushings, except that the front end sound has more of a
"back and forth" sort of repetition as the front suspension loads and
unloads.  the rear-end sound has more of an "around and around"
repetition that sounds sort of like something that is spinning is
rubbing against something rubber during part of its rotation, so that
there is a distinct start and stop to the short noise, and the
frequency of its repetition increases and decreases with road speed.
also, the sound changes in pitch and intensity based on torque; ie, if
i take my foot off the gas, it will change instantly, well before the
vehicle starts to slow down.  i also tried coasting at speed, and
though the sound got a little quieter the moment i disengaged the
clutch, it did not change at all as the engine settled down to idle.
so i'm pretty sure it is something in the drivetrain and not the
engine.

anyone have any ideas?  i don't want to take it back to fred's while
it is asymptomatic.... and i really can't figure out how it could be
so loud and consistent for 3 days and then disappear completely once i
got down off the mountain.

Ben.