>And speaking of fixing things under the van, recently the noise level from the 
>rear of the van has risen.  THere's a steady humming/whining noise coming from 
>the back.  It seems to only happen while the engine is applying torque to the 
>drivetrain -- if I back off the throttle it quiets down.  THe pitch does NOT 
>alter when I shift gears, indicating it's not a "gearbox" problem, but in the 
>final drive or axles/bearing.

How are the CVs? Driving in a tight circle slowly will make them clunk if 
they are bad, do a tight figure eight. It could be something in the final 
drive/diff section of your gearbox. Try putting it into neutral when on the 
highway and listen. That will take the load off the trans and let you hear 
the wheels/shafts. Swerve (gently!!) side to side to load up the wheel 
bearings and see if it changes.  Also any slop in the rear wheels? My '87 
drones due to a wheel bearing going...going..(gone). I'm not in a hurry to 
fix it yet! It is a bit louder when I push it harder, not much though. tim s.