What’s inside a Viscous Coupling?
Let’s remove the big circlip and take a look
It smells pretty rank, worse than burnt gear oil even
Ready to remove the plates………..
This is a driven plate, driven by the engine side via the outer splines/teeth
And this is coupled plate which drives the front wheels via the inner splines/teeth
And there’s a spacer between each coupled plate so there’s a gap of 0.35mm between adjacent plates, just room for the silicon fluid
Which was black in this example, but it is 19 years old and has done 108,000 miles so probably to be expected.
Take out the 49 plates and you have this empty case with the centre axle
All clean ready for refilling ?
So the inner splines drive the pinion shaft, shown here with the vc lid ommitted for clarity….whilst the vc case is driven by the input shaft which is in turn driven by the propshaft
Simple but clever……
