Date: Thu, 21 Jun 2001 10:27:56 -0400
Reply-To: Derek Drew <derekdrew@RCN.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Derek Drew <derekdrew@RCN.COM>
Subject: Viscous Couplings Arrived (Plus Why It Was 4 Months Late)
Content-Type: text/plain; charset="us-ascii"; format=flowed
Ignore this message if you are on the syncro list as it is a duplicate of
the message sent there a couple of days ago.
At 11:00 PM 6/16/01 +0000, you wrote:
>find anyone to work on it so he junked it. I found it and now is a
>daily driver with a little tinkering but am stuck on what to do with
>the VC. She has 115k miles on it. I have driven for a month now and
The shipment of OEM viscous couplings is now in Washington DC and I will be
putting them into the mail for list members beginning next Saturday. There
some left if you need one--just email.
I have some minor information to add about the VCs that may be of interest
to VC watchers. Then, further down in this email I will reproduce some
basic background about the VCs for the benefit of those coming to this
issue fresh.
1. The reason for the shipping delay was because the factory had issues
with the plates inside the VCs. That the plates would subject a shipment to
a delay that turned out to be four months may lend support to the factory's
previous admonitions that the torque characteristics of the plates is
critical, and that plates should not be reused. If there are rejected
plates, I hope they will not be sold through non-OEM channels.
2. This is trivia, really, but I found out that the factory used to rebuild
the VCs themselves!!! but discontinued this practice because, they said,
they could not get a consistent quality out of the rebuilds. I did not know
they had a rebuilding operation previously and that it had been shut down.
3. Proper balancing of the VCs is critical, and every VC has weights welded
on the outside in precise sizes and locations. It would seem to me that any
rebuilding of the VCs would throw the balancing off, and that the weights
would then have to be cut off and rewelded on to the correct locations.
4. I have received additional confirmation that VCs are sensitive to
vehicle weight and vehicle power. If you have a VC that you are wondering
about, try installing a Chevy V6 in your van and then put in two tons of
newspapers. If the VC is at all unhealthy, it will then bind like heck.
Before closing on the new information and totally as an aside I would like
to mention that Serge sent me photos of the 235/85/16 tires he mounted
experimentally on his 16" Vanagon and I have to say that even though I am a
fanatic about wanting to install this exact size, the tire on the face of
it looks simply too big. I will try to scan these extraordinary photos for
the list at a future time. But, as Serge felt, I am quite skeptical of this
size after seeing the photos. As it stands, it now looks like the best
choice for largest tire for syncro is the BF Goodrich All Terrain Radial
245/75/16.
This concludes any new information. All information below is reproduced for
the benefit of those who are addressing this subject fresh. If you perform
the tests below and decide you need a new VC, send me an email to find out
what is left and shipping details, etc.
Lastly, for those who have sent funds to get factory OEM CV Joint Boot
protectors, I received new information in the last two days that they are
on their way and should go into the mail within two weeks.
========================================================
Background (Description)
The Viscous Couplings I am bringing in for list members are brand new OEM
units and are not rebuilt. When you receive your VC you will notice that
the filling ports are sealed shut with a blue seal to indicate that they
have not been reopened to the air. In every package some extra viscous
coupling juice is loose in the container. This is normal after-effects of
the manufacturing process, and does not indicate a leaking VC.
If you are wondering about whether you need a new viscous coupling, here is
how to tell:
1. According to the manufacturer of the viscous couplings, the VC is only
built to last 100,000kms (about 65,000 miles). It would be silly to replace
it until it shows actual signs of failure, however.
2. The actual sign of failure is usually that the VC gets too aggressive
and starts coming on too much and too hard. In this case it is an emergency
because then your transmission components are fighting each other and you
can destroy them quickly. You can still drive around on a too-aggressive VC
without destroying your drivetrain if you remove the driveshaft from the
vehicle--but then, of course, you will not have four wheel drive. The
symptom that would cause you to know that your VC is too aggressive is
usually that when you enter a paved parking lot and you make tight turns
after a period of highway driving that the vehicle seems to want to stop as
though you had put the brakes on--the vehicle simply hates tight turns.
Sometimes there is a binding and bucking sensation while driving with the
steering wheel turned all the way to its limits. Some on the syncro list,
notably Ranier, think there should be *no* scrubbing of tires whatsoever in
tight turns, but I feel that a slight scrubbing or resistance to tight
turning is normal and will not hurt your car. When the scrubbing is enough,
after a period of highway driving, to actually cause your van to want to
stop then it suggests it is time to change the VC, particularly if you have
very high miles. (In support of Ranier's position, by the way, Mick Kalbner
of Hawaii reports that after changing his VC the scrubbing he felt went
away completely.)
3. Less often, the VC fails by simply not coming on at all and you do not
have traction to the front wheels.
4. The official factory test is well documented in the archives, but
basically, the test is to put a two by four in front of the front wheels
(the factory leaves out the two by four but in testing list members have
found that even the factory VCs are stiff enough to require the 2x4 to hold
the vehicle back) and then jack the rear of the vehicle up in the air with
a rolling jack under the car and then very slowly and carefully let the
clutch out in first or low gear. After a few tries you will find that you
can let the clutch out with the engine running and the VC will allow enough
slop to let the wheels stay still at one end of the vehicle without
climbing over the two by four while the engine turns the wheels at the
other end of the vehicle. If you cannot pass this test, then you should
consider buying a viscous coupling immediately in order to avoid destroying
your transmission. Be sure and perform this test soon after highway driving
for 20 miles or so or it may not uncover a problem.
More Background Stuff on VCs:
http://www.vanagon.com/syncros/technica/vc-expert-interview/index.html
http://gerry.vanagon.com/cgi-bin/wa.exe?S1=vanagon
and search on these parameters:
Search For > viscous
The author's address is or contains > drew@interport.net
Since > 1999
There is an excellent article by Steve on how to replace the VC at
www.syncro.org in the Tech section called "Replacing the VC (photos):
TIP: Try using a 1/2 inch wrench to take the bolts off the driveshaft when
undoing the driveshaft from the front diff. It makes it easier.
TIP: Mark the position of the driveshaft on the front diff so you can put
it back on in the exact same orientation.
=================================================
WHAT ABOUT REBUILT VISCOUS COUPLINGS?
=================================================
There are two companies in the USA selling rebuilt VCs. For more
information on these units, search the archives for posts containing Oregon
Transaxle or "rebuilt VCs" or "rebuilt viscous couplings."
Generally, the price of these units is somewhere around $600 or $700 last I
checked.
The issue with these units is that:
1. They leave no air in the VCs, which the factory says will destroy them.
2. They do not replace the plates. The factory says the plates must be
replaced. More recently after I asked about these issues, they started
advertising that they were replacing the plates as well, which is
interesting because there has been no supply of these.
3. They are experimenting with the right fluid to put into the VCs so they
are guessing at what to use.
The factory engineers who designed the viscous couplings sent me a slightly
more emphatic email from Austria about these VCs and here is what they said:
"Technical: What is being done by the company is in grave contradiction to
our experience. Leaving no air in the unit, will cause the unit to
disintegrate when going into the hump condition. Using a thinner fluid will
result in less torque transfer to the front axle, reducing off road
performance. If you can live with it, it`s o.k. The cause for a degraded
performance of a VC unit lies in a change of the physical shape of the
plates (microscopic wear of the burrs intentionally created when piercing
the slots. Thus rebuilding the unit without changing the plates at the same
time is an exercise in futility."
Note that notwithstanding these comments about VCs from the factory, Weddle
(based in southern California) in general has an excellent reputation for
working on Volkswagen transmissions, and is the premier rebuilder of syncro
transmissions in the USA. You can find out more about Weddle at
www.2weddle.com The two others I know about are Daryl at
www.aatransaxle.com [aatransaxle@juno.com] in the Pacific Northwest and
Dennis Haynes on Long Island, New York [NEW: dhaynes@optonline.net, OLD:
Dhaynes57@EMAIL.MSN.COM].) Dennis has rebuilt dozens of transmissions that
I know of, and is an extraordinary mechanical mind in general. He is a
logical choice if you are on the East Coast, Weddle if you are elsewhere,
and possibly Daryl if you are in the Pacific Northwest although I don't
know as much about Daryl's work first hand.
_______________________________________________
Derek Drew New York, NY
CEO & Co-Founder
http://www.ConsumerSearch.com/
===========================
"Best Expert Review Site"
for product reviews on the Internet
Jan. 2001, PC World Magazine
==========================
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