4motion behaviour on slippery slope

[c7pets]

Hello!

I have a question/observation about 2016 T6 150kw 4motion behaviour. Haven´t really tested it before, today thought that I would give it a try on slippery (muddy) slope. Turned off traction control (TC) and took off. Since I had some grip in the beginning of slope I managed to get a good start. At some point I got wheel spin, but instead of uncontrolled spin as expected, (because TC was turned off), something still occasionally "kicked in" making lot of mechanical noise and trying to stop wheel spin. As a result there was no moving forward anymore and the van was stuck. I would say that probably I would have "conquered" the slope if this "active wheel spin breaking" hasn´t interrupted. I thought that disabling TC would allow uncontrolled wheel spin, but seems it doesn´t completely turn it off? Can anyone comment?

Greetings
Peeter

 

[DXX]

Limited slip differential in action.

 

[c7pets]

Or maybe rather EDL which is also probably not disabled when turning off traction control?

Didn´t know about LSD existence...on which axel it suppose to have LSD?

Peeter

 

[mmi]

A quote from "VW Self-study Programme 414, 4MOTION with Four-wheel Drive Coupling Generation IV, Design and Function" -

Pulling away with slip (on ice or snow)​

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If just one wheel on the front axle spins, the electronic differential lock (EDL) will intervene by braking the spinning wheel and thus increasing the driving power of the other wheel.​

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Possibly the feature still exists also on T6's 5th gen 4Motion.

 

[dubber36]

What tyres do you have?

 

[c7pets]

I have more-less came to the same conclusion that it was probably EDL that kicked in. By the way, didn´t know about its existence until today, when stared to look around in this forum. Of course this brings me to another question - whats the difference between TC and EDL...as I understand both try to brake the slipping wheel? Or TC just cuts the engine power?

About tyres - I had badly worn summer tires, but the point of my "experiment" was to test 4motion after Haldex pump change and I was just curious if the 4motion allows random uncontrolled slip when TC turned off. I totally realize, its not an off-road vehicle, but I still believe that in some cases the unlimited slip should be allowed as its the only thing that keeps you going...

 

[dubber36]

I wonder if it's the ESP interfering? That can't be turned of, so if one wheel is spinning faster and the other wheel speeds are high enough, despite not actually moving, it could think you are on the brink of an accident, therfore applying a brake.

Saying that the ESP can't be turned of may not be strictly true. When my old Passat went on the rolling road, there was a sequence of turning the hazard lights and pressing the throttle that turned it of. I can't remember the exact procedure, but I imagine the Internet will know.

 

[Robert]

...there was a sequence of turning the hazard lights and pressing the throttle that turned it of. I can't remember the exact procedure, but I imagine the Internet will know.