HOW TO: Viscous Coupling Removal

After a bunch of inquiries on how to remove a VC, we decided to document the process of replacing a broken VC.

The background for this approach is the official “VW Vanagon Factory Repair Manual”.

Note: This guidance is not an official repair manual – it is just our recommended way how to do it. And we assume that every bolt can get opened easily – just one rusted screw can change the situation drastically.

Approach: We recommend to remove the whole axle-transmisson, even if it’s possible to just remove the VC. One reason is that it’s quite hard to unscrew the bolts from the lid of the axle-transmission. The trickier problem though is to work properly, because it is possible that dirt falls in the open axle-transmission. Also we advice to change the tranny-oil (1,5 Liter  75W90  API GL-5).

Fastening Torque:

  • Drive Shaft at Tranny:          35Nm
  • Cardan Shaft at Tranny:       35Nm
  • Axle-Transmission (M10):    45Nm
  • Housing (M8):                       20Nm
  • Oil Filler Screw:                    20Nm

1) Unscrew the Drive Shafts

Start to remove the oily dirt in the bolt heads of the drive shaft. After cleaning use a hammer to get the torx or heaxagon tool in the screw. After removing the drive shaft a plastic bag safes the joint from dirt.

Auskratzen der Schraubenköpfe
Removing the dirt

Inbus / Vielzahn eintreiben
Gently hammering

Gegenhalten mit Gripzange
using a vise grip wrench

Lösen der Antriebswelle
removing the cardan shaft

Fixieren der Antriebswelle
hold in position with some tie

2) Remove the Cardan Shaft from the axle-tranny

First mark the current installed position with some paint stick. Then unscrew the fine thread bolts. The nuts are self-locking ones and should get replaced (although no one ever does).

 

Befestigungsschrauben Kardanwelle mit 13er Schlüssel lösen


3) Ventilation and Speedometer cable removal

 

 

The ventilation of the transmission needs two copper sealing rings which should get replaced. The speedometer cable gets unscrewed with a 27 wrench.

Getriebeenlüftung
Ventilation

Tachoantrieb mit 27er Schlüssel lösen
Speedometer Cable

Only if you have a front diff-lock:

Remove your diff-lock actuator and bracket before your remove the differential. It is very difficult to actually remove the front differential with the actuator attached and not break it.

 

3) Remove the front tranny suspension

Remove both screws and the rubber bumper.

17er Schlüssel Getriebeaufhängung

 

Trägerblech vorne zum Getriebeausbau

4) Remove the rear tranny suspension

Remove the whole bent carrier and both rubber bumpers

Gummipuffer
rubber bumpers

Beide Schrauben entfernen mit 17er
remove both screws

 

5) Remove Axle Transmission

Remove the Axle-Transmission to the front. Without having a transmission jack, it’s a work for two guys. The weight is not the problem, but the tranny can suddenly come down while shaking it.

The best way is to put the tranny first back (as far as possible) and then pull down

Mit Getriebeheber abfangen

 

Und dann Ablassen

 5) Changing the VC

Unscrew all the M8 Bolts of the lid. With the help of a soft head hammer the lid can get open quite easily. Then remove the VC and the distance-ring. You can stick the distance-ring over the shaft using some grease.

 

Deckelschrauben mit 13er Nuß entfernen
Remove the lid-screws

Alte Visco mit Distanzring
VC with distance-ring
Dichtflächen säubern Distanzring mit Schmierfett

After using some sealing, put in the new VC. And pay attention to the maximum torque (20Nm) of the srews – the aluminium-threads in the housing get damaged easily.

Getriebe aufdichten
sealing

Auf Anzugsmoment achten!
torque wrench: 20Nm

 

6) Mounting

Now the axle-transmission is ready for re-mounting. The cardan-shaft should get installed in the former position (the rubber-element shows either to the axle-transmission (Diesel) or to the engine (Gasoline).

Pay attention that you have to fasten the screws of the cardan shaft first and afterwards the suspension-screws of the axle-transmission! Otherwise you will experience serious vibrations.