I suspect the local ECU controlling this GKN system knows the temperature of the fluid, and that's used in the software to make the clutch respond in a calculated manner. That's the sort of thing software in the company I work with does it. But, I don't claim to know.Viscosity changes all the time (with temperature), just like any oil does. See
this datasheet (that's what I use in my VAQ's Haldex unit):
RAVENOL AWD-H Fluid
RAVENOL AWD-H FLUID is a high-quality formula of high-performance oils with special additives and inhibitors. RAVENOL AWD-H FLUID is a special high-perfor...www.ravenol.de
It'll be triple digit cSt below freezing point and like 5 cSt when highly loaded
on a hot summer's day. I'm aware my knowledge has its limits, however I still
just can't imagine how that GKN clutch would be able to 'sense' viscosity . . .
I don't want to argue with you, I just want to broaden my comprehension.
.
The only time people have reported a problem that requires an ECU Re-Set is when the new fluid viscosity makes a significant-enough jump (don't know what that is...I don't know if it's sensing centi-stokes or whatever) that the calculation is now inaccurate. Gradual changes in viscosity as well as wear on the clutch is reportedly easily accommodated. In many ways, it makes sense to be sure and change this fluid early and often, so that the difference isn't enough to require a Re-Set. But, I'm not going to tackle it until I can get better information and confirmation. If I'd have simply gone with recommendations being thrown around casually by people that presented their recommendations as correct, I wouldn't have the correct rear differential fluid, nor the correct differential fluid level...and that's less complicated than this GKN system.
