Date: Tue, 28 Sep 2004 21:43:41 +0200
Reply-To: Robin Oomkes <roomkes@ZONNET.NL>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Robin Oomkes <roomkes@ZONNET.NL>
Subject: Re: New Member
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----- Original Message -----
From: "James Lowe" <james.lowe@COX.NET>
> 2) Front Differential Lock Actuator does not seem to work. I tested the
> four wheel drive small sandy hill and the front wheels didn't engage at
> all
> on a couple attempts and did on others. The 4WD did not engage when I
> pulled the knob on the dash. Also, the indicator lights on the dash don't
> work. Does anyone have experience they could share about this?
>
Hi James,
I don't have a syncro but I've just been reading the (European) owner's
manual of my new-to-me '88 Westy - as you say, the pull knobs that you
mention, if they are working, actuate the differential locks. This should
only be done whilst offroad at relatively low speed. They have nothing to do
with 4WD.
4WD is automatic on these cars. There is a wet clutch thingy called a
viscous (vicious, read on and you'll know wy) coupling between the front and
rear differentials. In normal driving conditions you get RWD only. When you
lose traction, ie. there is a considerable amount of difference in speed
between the front and rear axles, the coupling stiffens up and transfers
power to the front wheels.
The result of this is that in sand, even with a good viscous coupling, the
rear wheels tend to dig themselves in BEFORE the VC reacts and sends power
to the front. The vicious part is that viscous couplings tend to wear out
pretty quick if used without TLC and they are expensive to replace.
In working condition, pulling the diff lock knob actuates a vacuum switch at
the differential. This 'pre-engages' the diff lock. As soon as conditions
are right (not too high speed difference between left & right) the diff lock
will engage. (It's like pushing up with your foot on a motorbike gear lever
whilst accelerating. Nothing happens. Only when you release the power will
the gearbox shift).
Once the diff lock actually engages, a light should come on at the switch.
But again, this has nothing to do with 4WD as such.
Only in very rare cases do you have a third knob in the middle that lets you
manually activate 4WD. In this case the VC story doesn't apply and you will
have a fixed link between front & rear axles. This limits 4WD use to gravel
and snow, and you don't get the on-road safety of the syncro system.
Thus the preaching from the Transporter Manual, in the Authorized German
translation by Martin Luther. The bit about the motorbike is mine, though
:-)
Robin
1988 Westfalia Joker TD
2003 BMW R1150GS
