Hello,
        I'm relatively new to this list, but have enjoyed the info provided so
far - thanks...
        I've got an '82 Vanagon diesel which tonight on the way home started making
a knocking sound from the back end when the accelerator is pushed on - not
very loud, but consistent, and follows the speed of the vehicle, not the
engine (ie: different gears don't change the sound).  I can't tell you if it
hums  or knocks at highway speed - all that I can hear then is the engine.
At about 30 MPH is where I hear the knocking.  If I let off the accelerator,
it goes away.  I've had the van about a year, so I don't know the history
before then.  My first guess is a CV joint.  If you have other idea's, I'd
like to hear them.  If it is the CV joint, do these fail catastrophically
(ie: van stops moving, other things wrecked)?  If not, how long have people
driven on these before fixing.  We're supposed to leave tomorrow for about a
200 mile trip....
        Thanks again for any insight.
Chris