I figured it out.  After removing the pop rivets.....I put my hand
back in the door to hold the motor ..moved the motor into position so
as to be able to access the screws that attach the motor to the mount
assembly that attaches to the door.  I manipulated the motor so that
one at a time each screw was over one of the holes in the door thus
allowing me to access the screw with a drive. The screws that attach
the motor to the mount assembly had square holes for drive.  I do not
know what you call that kind of drive but I had one and was able to
remove the screws.  The screws were long and once removed the motor
assembly split in two which separated the motor from the drive
mechanism that has the cables that crank the window up and down.  I
removed the separated half which contained the motor assembly.

I first removed the service cover for the drive gear and what a mess.
A bunch of plastic pieces were in bits and pieces thus becoming
apparent why the motor was just free spinning.  The little plastics
pieces were the little cams which transferred power from the motor
drive gear to the shaft which spins the metal gear that meshes with
the gear mechanism of the cable assembly still left in the door.
I totally disassembled the window motor to clean the plastic pieces.
This caused the repair to take much longer because the brushes popped
out and the springs went sailing away never to be found.
I removed a couple of push button ball point pens to use their springs
for the tension the brushes need to push against the armature.  What a
time I had getting the brushes to stay after installing the brushes. I
had to carefully insert the grease seal with enough clearance
remaining to provide the stopper needed to hold the brushes in place
until I could put the cover back on.

I put the window motor all back together and reattached it to the
motor mount assembly with the long screws.  Then the mount assembly
had to be mounted to the door however there were no pop rivets any
more.  I used some 2 inch long machine screws with washers and lock
washers.  I routed the power cord to its connection and tested the
window.

WOW...the motor was is so quiet and works perfectly.  I attached the
speaker to the door and then installed the door skin. Made sure all
was back together.

I am now finished with door one with 3 more left.  I will get these
done this week at night in the garage.  

I took pictures but some of them did not focus too well.  I will take
some better pictures this week of the other doors.  I will post an
update about the project with picture info if you want.  Just let me
know here.

Thanks,

Sam in Raleigh.