This won’t interest most members but I am trying to get to the bottom of the “optional decoupler” puzzle.
In publication 500.2808.81.20, dated January 81985, Page 28, I find the following:
- An engagable/disengagable 4WD is also offered as an optional extra. In this case, the 4WD is “selected” by and via a Bowden cable, or by engaging the cross-country gear. The actual shifting operation is done pneumatically by a shift element.
- With this type of 4WD the viscous coupling is not required. The pinion shaft has been lengthened accordingly. It is supported in the axle housing by roller bearings. The output and pinion shafts are splined. A splined sliding bush couples these two shafts together. Engagement and disengagement is done by means of a shift linkage.
- Very good illustrations are shown with the text
It goes on to detail how 4WD is also engaged automatically when G gear is selected and that it should be used only on loose surfaces.
This answers a number of recent questions and ties up a lot of loose ends
We now know that:
- Disengageable 4WD was a factory option
- It was either a VC or a solid shaft, not both
Since the factory decoupler was vacuum actuated (via a Bowden cable), it follows that the German produced aftermarket decoupler nose cones are very probably a replica of the original, thus giving some weight to aftermarket claims.
The only question left hanging now is that I can’t find any reference to disengageable 4WD being an option for Australian delivered Syncros. I have VAG brochures from the time of introduction in Australia but it doesn’t get a mention. Sales persons at dealerships weren’t well acquainted with the Syncro, so they weren’t of much help. In fact, the VW dealer in Camberwell Road , Hawthorn (Vic) flatly denied that such a vehicle existed. I went back there the next day with a recent cutting from The Age. It was half a page and half of that was a most impressive pic of the white double cab thundering over the Nullabor on the Australian leg of the world introductory tour. They were extremely embarrassed but totally unapologetic for their incomprehensible ignorance.
Les
PS: Hartmut, thanks for reminding me – I had been racking my brains but the name of Matthias Dinkelmeyer had escaped me.