Why does the Freelander Viscous Coupling seize? And how to check it.

The freelander has 3 main drivetrain problems, the Intermediate Reduction Drive (IRD), Viscous Coupling(VC), and the rear differential.

The reason for this is the front wheels on the Freelander are driven faster than the rear wheels so that it handles well, like a front wheel drive car. To accomodate this ratio difference a VC is fitted inline with the rear propshaft which is constantly slipping.

On the earlier models this ratio difference was too great resulting in the VC working overtime and failing by seizing solid. Now with this locked, the front tyres are fighting the rears as the transmission is 'winding up', initially this just wears the tyres (causing a saw tooth effect) but it also puts increased load on the IRD and rear diff as they are fighting each other , thus causing rapid wear in both and ultimately failure of one or both.

To check the condition of your Viscous Coupling unit,

1. Jack up on of the rear wheels,
2. Put an 18" bar through the rear prop UJ  and try to turn it.
3. It should turn slowly with resistance.

Please note even a good VC will be quite tight. A seized one will feel like the handbrake is dragging when reversing slowly on full lock. If your unit is seized then it must be changed as soon as possible.

Courtesy of Ashcroft-Transmissions

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