Test Viscosity Coupling Possible?

[Norge]

Gents,

This what happend: Driving up a rather steep road I had to stop and due to ice under the snow my car started sliding down for 7 meters before a tree stopped me (fortunately). After a stop and wondering how to out of this position, I startet engine, pushed 4-wheel drive button and started to drive...well the only wheel going around was my left front wheel, the rest was not moving. Although I had pushed the 4-wheel drive button, nothing happend except for the motor going down i RPM's.

My garage told me the next day that I had to keep the left wheel spinning around for ca 30 secunds to get the viscosity coupling active.

If have to admit that I do not remember how long I kept the wheel spinning but for my feeling it was a long time.

My questions:

- is this a correct statement from my garage?

- how can the functionality of the viscosity coupling be testet?

- can I test/check it myself without being in a unpleasant position?

Thanks,

Henk

[Norge]

Car info: RAV-4 from march 2008

[anchorman]

Henk

Your garage is talking rubbish.

There is no viscous coupling, it is a computer controlled multi plate clutch. The problem is that even with the 4WD lock button pressed the computer still overrides if there is a very low friction surface like pure ice or snow on a steep hill. However, it is possible to take away the traction control which MIGHT help. Look at the link in the pinned section for disabling the VSC for MOT and give that a try. Its easy after a couple of practices.

[Norge]

Henk

Your garage is talking rubbish.

There is no viscous coupling, it is a computer controlled multi plate clutch. The problem is that even with the 4WD lock button pressed the computer still overrides if there is a very low friction surface like pure ice or snow on a steep hill. However, it is possible to take away the traction control which MIGHT help. Look at the link in the pinned section for disabling the VSC for MOT and give that a try. Its easy after a couple of practices.

Anchorman, thanks for your reply which scares me a bit as it seems my garage is talking rubbish.

I found your article If I understand you correct would all 4 wheels start moving after I would have disconnected the VSC (real 4WD situation)?

Do I have to push the 4WD button before or after the brake/hand brake method? Or is this not important?

[anchorman]

When you disable the VSC you will see the orange "skidding car" symbol light up on the instrument cluster. Press the 4WD lock after this has lit and make sure it stays lit.

Even in this condition the front and rear axles have a differential so in theory when one fron and one rear wheel spins you are still stuck. It really depends on how slippy the surface is. You could try starting in 2nd gear or you might have to try rocking the car backwards and forwards.

[Norge]

Thanks, I will practice (and put a print out in my car) and hope I will never ever have to use it ;)

My regards,

Henk Jan