Just thought that you guys showed see what German Transaxle in OR. states in 
their paperwork that comes with your new transmission and VC. The paper work 
has been scanned, so there may be a few spelling mistakes. See ya, Michael
 87 syncro
 87 quattro
 
 What you should know about Vanagon Syncro viscous couplings (and why we have 
a limited warranty on them. and why you may not want to install one):
 
 We have had a fair number of viscous couplings and/or front differentials 
returned to us as �locked up�; every one of these units tested just fine on 
our bench. And upon inspection the coupling had no defect whatsoever The 
Vanagon viscous coupling is a very simple device for transmitting power to 
the front wheels of the vehicle. Basically, it consists of a shaft from the 
driveshaft going Into the coupling, and a shaft going out of the coupling to 
the front differential. There is no direct mechanici coupling between the two 
shafts. The only connection between input and output is via a very thick 
(viscous) silicone fluid; you could call it an almost zero-slip torque 
converter. The job of the viscous coupling is to allow a very small amount of 
slippage between the front and rear wheels (for going around turns), while 
giving full power to the front wheels should the rear wheels start to slip In 
snow or mud.
 
 Viscous couplings �fail� when they overheat and lock up solid, no longer 
allowing any slippage at all. When this happens the van binds up and does not 
want to move in even the slightest of turns.
 There are two situations which cause churning or overheating of the viscous 
coupling:
 1. Driving the vehicle with anything but 4 absolutely identical tires. If 
all tires do not have the exact same rolling circumference, the front and 
rear axles will be turning at different speeds. This will cause the coupling 
to churn, cook itself and can cause damage to the entire drivetrain.
 2. Having ANY misalignment, either up/down or left/right, of the 
engine/driveshaft/front diff. Huh? Here�s the deal: if the 
engine/driveshaftlfront diff are not in an absolutely straight line with one 
another, the driveshaft will be slightly speeding up and then slowing down 
with every revolution. This causes a churning within the viscous coupling, 
which will immediately bind up the unit.
 
 THEORETICALLY, THE VISCOUS COUPLING SHOULD NEVER GO BAD, IF EVERYTHING ELSE 
IN THE VAN IS OK IF YOUR CUSTOMERS HAS GONE BAD, SOMETHING HAS CAUSED THIS TO 
HAPPEN. THERE IS EVERY REASON TO BELIEVE THAT THE
 SAME THING WILL HAPPEN TO OUR UNIT! ARE YOU SURE YOU WANT TO GET INTO THIS 
BAG OF WORMS?
 
 When your customers car left the factory, you can be sure that the 
drivetrain was perfectly aligned In every plane. Since then, how many times 
has the engine been out? How about the driveshaft? Front duff moved around to 
change front CV joints� Any of these activities can cause misalignment of the 
drivetrain, which will cause the viscous coupling to churn and lock up. If 
your customer complains of binding, we suggest this quick test: with trans in 
neutral, engine off, jack up the right front wheel. Put a socket on one of 
the wheel lugs, and about a 2-foot breaker bar on the socket. You should 
verrrrry slowly be able to turn the wheel, with great difficulty. Wont turn 
at all? Let the van sit overnight, and try it again in the morning, stone 
cold. If you can turn it when cold, there is nothing wrong with the coupling; 
something is causing the coupling to churn when driving, locking up the 
coupling.
    Since we have no control whatsoever over the condition of the vehicle in 
which our viscous coupling and/or front differential is installed, we cannot 
cover installation costs for front differentials/viscous couplings replaced 
under warranty if we get our unit back and find no problem with it. Happy 
trails...
 
The difference between U-joints (which the drlveshaft has) and cv (constant 
velocity) joints, Is just what the name Implies. The more expensive CV joints 
tum at constant speed regardless of angle, while U-joints speed up and slow 
down with every revolution, unless they are absolutely lined up wIih whatever 
they�re tumlng. Prove it to yourself with a sir universal Joint and a couple 
of extensions.
 German Transaxle of America, me
 
 Service/Warranty Bulletin: VW Vanaaon Svncro 4WD
 It has been brought to our attention that transaxle failure in 4WD Vanagons 
c happen simply by having different sized tires being fitted to the front and 
re wheels of the vehicle. Here�s why: the Syncro van normally drives the rear 
wheel there is, however, a driveshaft coming out of the front of the 
transaxle, going the front of the van, where it attaches to a �viscous 
coupling�, which is in turn attached to the front differential which drives 
the front wheels. The visco coupling is a simple clutchlike device which 
locks up solid if there is a differen in speed between its input and output 
shafts. When the vehicle is underway, the re wheels normally drive the car, 
with almost no power being transmitted through t viscous coupling to the 
front differential, because front and rear wheels are ho turning at the same 
speed. However, should the rear wheels start to turn a different
 speed from the fronts (slipping in snow, ice, etc.),i$~e viscous coupli
 instantaneously locks up, sending power to the front wheels. It stays locked 
as long as there is tension on it (that is, as long as front and rear are 
trying to turn different speeds). As soon as full traction is regained, all 
wheels are turning at same speed, and bingo, the viscous coupling relaxes; 
once again, power is going the rear wheels.
 
 You can observe the functioning of the viscous coupling Like this: find an 
empty parking lot, get the Vanagon going about 20 mph, and slip it into 
neutral. Then coast normally. Now turn the steering wheel to the right or 
left, and crank
 farther and farther. You�ll feel the van bind up, slow down, and quickly 
come to
 complete stop if you turn the wheel far enough. This is because in a sharp 
turn the front wheels of any car turn a different speed from the rears. In 
the Syncro Van thus causes the viscous coupling to lock up and try to get 
both front and rear wheels turn the same speed, but it can�t, because you�re 
on pavement. The whole drivetrain is now in a bind, fighting against itself, 
which brings the van to a stop.
 If you�ve been following this, you�ll now realize why you can�t have 
different
 tires on the front and rear of the Syncro Vanagon: THE VISCOUS COUPLING WILL
 LOCKED UP CONSTANTLY, TRYING TO GET BOTH FRONT AND REAR WHEELS TO TURN AT 
THE SAME
 SPEED. TIRES OF DIFFERENT CIRCUMFERENCE OBVIOUSLY CANNOT TURN AT THE SAME 
SPEED,
 AN ENORMOUS STRAIN IS CONTINUALLY BEING PUT ON THE ENTIRE DRIVETRAIN
 SPEEDS. THE TRANSAXLE WILL GROSSLY OVERHEAT AND BE DESTROYED.
 IT IS ABSOLUTELY NECESSARY THAT YOU CHECK THE CUSTOMER�S CAR TO~SEE THAT IT 
HAS
 IDENTICAL TIRES. NOT JUST THE SAME SIZE. BUT THE SAME MANUFACTURER AND TREAD 
DEPTH
 FAILURE TO DO SO WILL CAUSE DESTRUCTION OF THE FRONT DIFFERENTIAL AND/OR 
 TRANSAXLE DUE TO OVERHEATING!   WE WILL NOT REPAIR UNDER WARRANTY TRANSAXLES 
WHICH
 HAVE  BEEN  OVERHEATED. OUCH! IT  IS  CRITICALLY  IMPORTANT.  (AND  
POTENTIALY
 EXPENSIVE)  NOT  TO  INSTALL  OUR  TRANSAtLE  UNLESS  THE  VEHICLE  HAS
 IDENTICAL  TIRES.
 Volkswagen doesn�t mention this possible problem in their owner�s manual (u, 
please give this sheet to the customer. If you have any questions, please 
call us
 Thanks!
 We strongly recommend the use of Redline MT� 90 synthetic gear oil in all 
Vanagc transaxles. They will shift easier and last Longer.
 

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