one of those BTDT answers......

I take it the socket is stripped/rounded out?
Get a propane torch, preferably one of the hotter
swirl combustion ones, a hammer and a 6" cold chisel,
dull is good here.

Go back under and clear as much alum'n crud off from
around the plugs, use a brush/etc.  Then hit it with
the heat, not red hot! just enough that sharp corners
and surface show heat flecks. You're burning off some
corrosion bits. Put the torch aside and hammer and chisel
at it, working on opposite sides and trying NOT to
shear off the plug flush with trans. It should jolt
loose, keep applying heat every couple of minutes.
When chiselling aim inwards a bit too, to separate
the plug from the trans/threads.  It's the alum'n crud
holding it, and that will weaken with the heat. Have
faith, this works. You will likely have to set the chisel
in 3 or 4 places before it finally shifts. Throw the plug
away when done!!!!!!!

When out clean the threads up with a wire 'toothbrush',
and apply nev'r-seize/similar to them/plug. Do not
overtighten, the plug threads are taper type, meaning it
doesn't tighten down like a normal nut, but generates huge
wedging forces to seal the threads.  You don't get as clear
a warning that the plug is ample tight because of this, a firm
extra 1/4-1/2 twist like the oil filter will work fine.

HTH, thanks for 1.9l FI help, so far a dead temp sensor, a corroded
but intact looking ground strap and ground wires/bolts have been fixed
and things are way better, Starts fast on the key without having to just
about floor it while spinning the starter for ages. One small step
for vanagon-kind....    If anyone has a real digijet manual and could
scan it and submit to Darrel Boehler for his website that would be great.
The L-jet + lambda for 2.0l aircooleds is there, and the 2.1l wasser's
digifant is too, but not the digijet.  Tim