For over a month i have had this annoying and sometimes expensive
sounding rattle from the rear end of van, mostly when accelerating (or
going up hill) in 3rd and 4th. David B. noticed it too when we were on
our V. Island trip. I had nightmares of transmission problems, or
engine internals...

I found out what it was yesterday, it was the horizontal exh. pipe
that runs across, behind engine, just in front of the muffler. I had
bashed it a bit on a logging road trip and it was bent just enough to
hit the muffler mounting brackets under just the right conditions. I
pried it away from brackets and the noise has gone.

Sometimes you get lucky :)

alistair