Lawrence and Martin - I belive that the main reason a front diff = lock was not available in the USA is due to the fact that when the front axle is = locked while driving on a good road surface, virtually all steering is lost and = the van keeps going straight on when it gets to a bend.  Over here an = accident would be put down to "pilot error" - but I suspect in the USA = the manufacturer would get sued!  Below are copies of earlier posts = from Tim Smith  (smitht@pop.unb.ca) = which I think answer your questions:
 
Don McCallum (1992 T3 1.6 TD = Syncro, 1986 T3 1.9 Camper, North Wales, UK)
 
Hi = Don,
 
I've machined out the front diff to take the locker components from = the
rear, they are all identical. Derek's not the only one with a front locker
this = side of the pond :) They do rarely come up for sale too, as new units
from Germany.
 
I've used an Audi Quattro locker control panel, = fits beautifully under dash
lip, includes a cig. lihter too. Much nicer = than the VW version, one click
of a nice big dial gets rear, another click = gets front added on. I can
lock/unlock faster and with more certainty, the VW = knob/valve is pretty
cheap plastic and had cracked already.
 
I = can't run the diffs independently, but doubt I would ever want to.  = I
wired up the Audi PCB for it's LED indicators, works fine. No blinking.
Tried it = first with the VW panel, there is only one PCB in my VW panel, = just
LED/bulbs, no flasher cct. How is yours put together, with an extra
'mini-board'? = My Syncro came fully wired for the front locker, just
connected it up at the = diff switch and front LED came on!  maybe winken und
blinken was a = later modification, handling does suffer with front engaged,
not a bad idea = the warning.
 
Hi Derek/Syncronauts,
 
short answer, ALL = locker/servo components are same in both ends. Remember,
SDP designed the system = NOT VW ;).
 
My front locker was built from a dead trans rear = locker. I machined the case
myself. You keep your old front R&P however, = just swap the ring from
non-locker to locker carrier, and set it up properly = :(.  Indicator switch
wiring is tied up to bottom of the chassis, nothing electrical needed.
 
Control panel on dash is now from Audi = Quattro, nicer, single dial to twist,
one click for rear, two clicks for both, = way better made valve body, same
LEDs to light up (I use Audi centre diff = as front locker LED), and I got a
bonus cigarette lighter out of the = deal.  Easier getting on/off the lockers
when turning in soggy cramped = places. Low profile, fits/looks nice under the
dash lip, after a bit of carving = (of Audi panel). Extra vac. line was also
taken from Audi.
-----Original Message-----
From: = Lawrence Dongilli <buspilot@WORLDNET.ATT.NET&g= t;
To: Vanagon@VANAGON.COM <Vanagon@VANAGON.COM>
Date: = 26 August 1998 14:58
Subject: Re: Syncro front diff lock: availability and conversion?

>I am also interested in any = information regarding the following post -
>
>Lawrence
>
>----------
>Martin Peitz wrote:
>
>> I've been wondering about the availability of = the front diff lock in the
>> Syncro here in the US.
>> I = have never seen one equiped like that in the US, but maybe its a
>> = regional occurance. Canada may again be different.
>> In Germany, where = people order cars in the configuration they want them
>> in from the = catalog and option list, I have seens lots of front diff
>> = locks.
>> In the US most Syncros seem to have been sold with the rear lock only,
>> but some no-lock-at-all cars are = around.
>
>> Does anybody know anything more about the VW sales approach = and
>> statistics on this.
>
>> I am contemplating to convert a = front diff to lock using the setup from
>> the rear = lock.
>
>> I remember somebody doing this before. Who was this? Please contact me.
>> It is interesting to note that the front diff lock = components do not
>> list in the US parts fiche, but of course do show in the = german fiche.
>> This speaks against availability in the US, but then = anything is
>> possible in the confused VW sales organization.
>
>> Anybody have a front diff housing for = lock laying around, maybe you
>> folks in = Europe?
>