I guess this could be down to the fluid level in the viscous...

> -----Original Message-----
> From: Brent Christensen [SMTP:bpchristensen@mindspring.com]
> Sent: 21 April 1999 16:17
> To:   Syncro@onelist.com; Vanagon list - post
> Subject:      [Syncro] Viscous Coupling survey
>
> From: "Brent Christensen" <bpchristensen@mindspring.com>
>
> I think it would be interesting to see how many of the Syncros out there
> will idle freely at 1,000 rpms with the rear wheels spinning in the air
> and
> not engage the front wheels.  If you have a Syncro and a floor jack with
> wheels it is a relatively simple test.  If you have time, please try it
> and
> report back to the list.
>
> My Syncro will engage the fronts at the  full 800-1,000 rpm idle speed,
> but
> if I slow the rear wheels down a bit using the hand brake, then the fronts
> will disengage.  I wonder if my VC is toasted...  ???.  (The fronts grab
> while making sharp turns in parking lots, but don't seem to act up at
> "road"
> speeds.
>
> Brent Christensen
> '89 GL Syncro Westy
> '91 Taurus SHO (For Sale)
> '95 Cherokee Sport
>
> ----- Original Message -----
> From: Dr. Rainer Woitok <woitok@rrze.uni-erlangen.de>
> To: Joel David Shortlidge <shortlid@expert.cc.purdue.edu>
> Cc: Steve <Steve@Schwenk-Law.com>; <wt@iscnet.co.uk>; <Syncro@onelist.com>
> Sent: Tuesday, April 20, 1999 3:55 AM
> Subject: [Syncro] Re: Viscous Coupling
>
>
> > From: "Dr. Rainer Woitok" <woitok@rrze.uni-erlangen.de>
> >
> > Joel and all others,
> >
> > On Mon, 1999-04-19 15:55:41 -0500, Joel David Shortlidge wrote:
> >
> > > ...
> > > How can you tell your VC is frozen???
> >
> > VW's original (German) repair manual doesn't say much  about how to test
> > the viscous coupling.  They only recommend placing the  rear wheels in a
> > break testing stand.  If you then switch to  the G-gear (creeping gear),
> > the front  wheels should move the van  out of the  test stand as soon as
> > the engine is revving slightly above idle.   If the front wheels fail to
> > do so the viscous coupling is to be replaced, VW  says.  VW adds another
> > tiny sentence  to this, saying that only  when the engine  is revving at
> > idle and with the G-gear  switched in, the viscous  coupling is able  to
> > absorb all the torque to the front wheels and keep them from moving.
> >
> > To me  this   last and  rather   ill-formulated (in the  German  manual)
> > sentence is the key to testing the viscous coupling.   For in most cases
> > we  are not dealing with viscous  couplings doing less than their share,
> > but rather with hard-going viscous couplings  which don't have a problem
> > at all in  moving the van  out  of the  test stand with  the engine just
> > idling.
> >
> > Thus the really important thing here is not the van successfully leaving
> > the test stand.  On the  contrary, the important thing  here is the  van
> > not moving and staying put in the test stand with the G-gear switched in
> > and the engine just idling.  If your  Syncro doesn't pass this test your
> > viscous coupling is probably  worn out and  ready for a replacement.  Or
> > put  the other way  round: as  long  as your van's  viscous  coupling is
> > working properly you will not notice your van has got one.
> >
> > As   soon as   you are encountering   problems   with your Syncro   when
> > cornering, in particular after a long and  fast drive, or  as soon as --
> > despite  of power  steering --  steering becomes   a  bit difficult when
> > turning and the Syncro slows down considerably when going round a corner
> > ... as soon as one or  more of these  things are happening, your viscous
> > coupling is most  probably due  for  replacement.  When  the tires start
> > whining while cornering it might well be too late already ...
> >
> > Hope this helps.
> >
> > Sincerely
> >  Rainer
> >
> > '89 Caravelle GL Syncro 16"
> >
> >  ----------------------------------------------------------------------
> > | Rainer M Woitok                  | Phone: (+49-9131) 85-27811,-27031 |
> > | Regionales Rechenzentrum         |                                   |
> > | Friedrich-Alexander-Universitaet | Fax  : (+49-9131) 30 29 41        |
> > | Martens-Strasse 1                | Telex: d 629 755 tf erl           |
> > | D-91058 Erlangen                 |                                   |
> > | Germany                          | Mail: Woitok@RRZE.Uni-Erlangen.DE |
> >  ----------------------------------------------------------------------
> >
> >
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