Listen to your uncle.  This is a common problem.  I have encountered
it on 3 different vanagons, usually after an hour or two at expressway
speed.  Usually it would be OK after cooling down.
  One common solution is to install a 50 amp relay near the starter,
perhaps under the back seat.  The relay is operated by the current
from the ignition switch which originally went to the solenoid.  When
the relay is activated it connects the large +12 terminal on the
starter to the solenoid control terminal.  Some of our favorite
vendors sell a "hard start relay" kit.
  The original setup has about 35 amps flowing thru the contacts in
the ignition switch, then thru barely adequate wiring all the way to
the starter.  As the years pass, the contacts in the switch wear, the
connections corrode, and the solenoid gets a little gummed up.
Eventually these things add up to trouble.  With a MT we could park on
a hill or get everybody out of the van to push.  With an AT we had a
hammer; usually having one person turn the key while the braver
volunteer went underneath to whack the starter.  It is said that the
blow can be struck by using a broomstick or the like inserted past the
rear tire.
   Since the ground for the solenoid is thru the circuit of the
starter itself, if the brushes get bad enough, the solenoid will not
operate regardless of the other circuitry.  Then it is time to have
the starter rebuilt.

Have fun,
Larry A.

On 12/14/09, Bobby Brown <bobbybrown1@gmail.com> wrote:
> Just got back from about a 500 mile round trip, everything ran great.
>
> Went to crank it up and no nothing from starter. I've got lights, radio,
> etc. Battery says 12.7v. I can hear the fuel pump.
>
> My uncle says to take a hammer and "bang" on the starter a few times to
> loosen the soleniod?
>
> What gives? What is the path to diagnose? I'm lost.
>
> --
> Bobby
>