Freelander 1 Viscous Coupling Unit: Do You Have A Problem With Yours?
The viscous coupling unit sits halfway along the vehicle between the front and rear propshafts. In normal driving conditions the front wheels do most of the work and the fluid in the viscous coupling unit flows easily. However , when the wheels start to slip in icy or muddy conditions the fluid stiffens and causes the rear wheels to engage and four wheel drive kicks in. As the vehicle moves out of the ice/mud the wheels begin to spin at the same speed again so the viscous fluid begins to flow more easily again and front wheel drive is resumed.
The most common way that a viscous coupling unit fails is that the fluid inside it is constantly in its stiffened state. This puts immense strain on the powertrain line resulting in failure of the IRD unit and rear differential. If you put your vehicle onto full lock and it feels tight as though the brakes are being applied the viscous coupling may be at fault. Other signs include uneven tyre wear or the VCU becoming hot after travelling just a few miles. A VCU lifespan is generally between around 30,000 and 70,000 miles dependent on driving conditions. When you change the VCU it is also recommended that the 2support bearings are also changed. As you can see from the way the VCU works having mismatched tyres will have much the same effect over a period of time as the viscous fluid will always be under strain and eventually the unit will seize. It is therefore crucial to match the tyre size, type and manufacturer on all 4 wheels of your Freelander. Although in an ideal world you would change all 4 tyres ay the same time, economics dictates that this is not always viable. Therefore it is recommended that you change tyres in axle sets and ensure they are of the same type, size and manufacturer as the ones already on the vehicle. If you need a new viscous coupling unit or support bearings, or just need a little more information please contact us.
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