Date:         Fri, 2 Feb 1996 00:05:50 -0500
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         DHaynes57@aol.com
Subject:      Re: Syncro Operation?

In a message dated 96-01-31 00:39:34 EST,
Wiesner_Craig@mm.ssd.lmsc.lockheed.com (Wiesner Craig) writes:

>I just bought a '86 Westfalia Syncro.  I have tried to find out how the
>Syncro
>is supposed to work and nobody seems to know.  A lot of people "think" they
>know how they are supposed to work, but it all sounds like BS. The guy I
>bought it from said that I had power to the rear all the time and when there
>was any slipage in the rear, power is automatically transfered to the front
>tires.  He said that the only time I would lock the differential is if I was
>stuck.  I own a 4-WD and always lock the front hubs when I am driving in the
>snow or sand.  Why wouldn't I want to lock the differential if chains are
>required or if I am driving over sand to PREVENT from getting stuck?  Also
>when I make a tight turn and turn the steering wheel all the way to one side
>or the other there is a definite resistance as if the front tires are not in
>synch with the rear.  Is this how it is supposed to be?
>
>Anybody know for real?
>                                                                        -
>Craig
>
>

Above operation description is basically correct.  The rear wheels are
coupled just as in a normal Vanagon.  In fact, you can remove the driveshaft
going to the front and drive the vehicle with no ill effect.  In fact, van
will ride and handle better on dry pavement.  The front differential contains
a Viscous coupling which compensates for the front and rear tires traveling
at slightly different speeds as they always will.  This coupling is filled
with a "special" fluid that thickens up when heated slightly.  This heating
occurs when ever there is a large  difference in speed between the front and
rear tires.  This system is sensitive enough that the difference in speeds
from turning the vehicle causes the coupling to "Lock Up".  Thus the
resistance you feel.  In normal 4x4 this is called Windage.
The rear differential lock is actually a mechanical device that actually
locks both rear wheels together.  It must be used properly as internal damage
can occur easily.  If you lock the rear, you will find it difficult to steer.
 I've been in mud and almost lost control as the van only wanted to go
straight.  It should never be engaged at a great speed.  Somtimes, you may
have to steer sisde to side slightly to get the unit to engage or disengage
as teeht have to line up in the Diff.
It is extremely important that all 4 tire be a "matched set".  Both brand and
condiditon.  Diffrent rolling diameters will destroy the viscous coupling and
both Final drive assemblies.
Hope this info helps,
Keep on Bussin,
Dennis.