Haldex Riddle

[George Selby]

At 11:53 AM 11/20/02, you wrote:
>A magnetic lockup wet multiplate
>clutch (ala scoobie) is a VC as well.


Actually, Subaru uses two different systems (at least on my model year)
depending on whether you have a manual or automatic tranny.

The manual tranny AWD system uses a VC (viscous coupling), which is the
version I have.  You can feel it work if you drop the clutch on loose
terrain, initially the front wheels spin, and gradually the rears kick in
and you take off.  The automatic tranny AWD system uses a wet
magnetically-controlled lockup clutch (controlled by the computer to allow
up to a 90/10 torque split between front and rear.)  This is not a VC, it
is a mechanical clutch system (slippage is allowed by the computer locking
and unlocking the clutches.)  Interestingly, to allow for towing, you can
pull a fuse and the rear driveshaft is disengaged (the clutches won't lock
up) and you can tow the car on a hook (or test emissions on a chassis
tester in 2wd) safely.

George Selby
83 Audi Coupe GT
92 Subaru Legacy AWD
gselby4x4 at earthlink.net

George Selby
70 F-100 Ranger XLT 460 C6
78 F-150 4x4 400 4 spd
85 Dodge W-150 4x4 340 TF727
83 Audi Coupe GT
86 Nissan 300ZX
85 Chrysler 5th Avenue
gselby4x4 at earthlink.net