Things they don't tell you about your AWD Subaru

[XR650L_Dave]

I've had torque bind problems on my 95 Legacy 5MT.  They initially toldme
they'd have to drop the transmission and replace the fluid coupling in the
centre differential - 900$ part, about 4 hours labour.  If I just left it,
it would eventually melt and I'd still have an AWD vehicle, only with an
open centre differential.  I should also expect to replace the half-shafts
more often due to added stress.

Luckily I also needed new tires, so I did that first and lo and behold the
torque bind went away never to be seen again!!

Just remember to rotate 'em and make sure the tread depth is the same
on all 4.

Dave

 

[Yousuf Khan]

Hi All!

Two words: Torque Bind

Inside of your AWD transmission is a clutch pack which allows the rear
drive to "slip" a bit during tight turns and such, thus eliminating
the klunk-klunk-klunk noise/sensation (torque bind) you would get
otherwise.

Fine and dandy, but what do you do when this clutch begins to wear
out?

Sadly, as far as I can determine, you buy a new transmission; $3,500
for a manual box, and (gasp) $5,500 for the automatic version.

I replaced the manual transmission in my wife's '02 Forry (140K miles)
last weekend for this very reason. Fortunately, I was able to locate a
reasonably low milage specimen at a local salvage yard, but what
happens a year or two down the road when _all_ of these cars have
accumulated enough milage for the AWD clutch to be questionable? Gonna
be real tough to find a good used one, I can guarantee that!

Although what you described is possible, it's not possible for a manual
transmissioned Subaru. The manual transmission version of Subaru's AWD
doesn't use a clutch pack, it uses a viscous coupling system. The clutch
pack was used on the lower-end automatic transmissions fitted to
4-cylinder engines. The viscous coupling becomes less viscous with
heating, thus harder to move through; the speed differences between the
front and rear drive shafts cause the fluid to heat up and become firmer.

A possible way this could be a problem is that if the front and rear
tires have worn away at different rates and now have different
diameters. This might look like torque bind, but it is easily remedied
with new tires bought for all four wheels at the same time.

Yousuf Khan