Today I began working on the traction issue with my 84..Unlike me..because
I usually wait till there is snow on the ground before I try to address
issues like poor traction, etc..but I recalled last fall, trying to back up
on slick grass to get into my shop with the van, and also chaining up to
make a silly little hill.. I lived in the Rockies for over 20 years and I
NEVER had to chain up..but with the van, I can't even make my driveway when
it gets slick...
  A few observations:  First, the rear suspension travel is pretty pathetic,
at least on my 84 it seems to be.  Didn't measure it for 'droop', but it
seems like the rear wheels only have a few inches of travel.  So I'm
guessing it takes very little to lift a wheel  or at least greatly diminish
the weight on a rear corner...
   I had a feeling my van was not very well balanced, corner to corner.
I've noticed that the right rear wheel always seems to spin with ridiculous
ease in low traction situations.  I could see, with my carpenters eye, that
the left front seemed a bit low and the right rear seemed high..So, I took
my tape and did a 'quick and dirty' check.  Indeed, the left front was low,
the right rear was high..by about an inch..Now, I know measuring body panels
is not accurate, but I think this van is so wacky that it gave me a place to
start..
  Now all the previous ride height adjustments I've made have been on true
coil over suspensions, and what I wanted  was to lower either the right
front or the left rear, in order to even up the load on all four
wheels...Like cutting off the legs of a rocking table, right?  Looking at
the front suspension..no deal there..Too complex and not any provisions for
adjusting the ride height (or the load on wheel)..So, to the back I went,
thinking to extend the spring, at least for now, on the right rear, the one
that has  almost no load on the wheel...Actually lowering the left rear is
what I wanted, but that was not looking easy at all.
  So, I jacked it up under the bottom of the a-arm, compressing the spring
at the right rear.  Clamped the coils and released the shock, then dropped
the A-arm, making some room at the top of the spring to add two 1/8"
aluminum plate donuts as spacers..
  We shall see if that improves the traction any, by putting a more even
load onto the rear wheels...actually kinda like sticking a matchbook under
the kitchen table to stop it from rocking...
  Not quite as precise as putting my Porsche racecar onto four digital
scales and adjusting the coil overs to within a lbs or two, corner to
corner...but maybe now I will be able to back up on grass, at least as a
start...
  Don Hanson