95 legacy awd system problem

[mark]

My 95 subaru legacy's awd system is not working, it only has front
wheel drive. On a hoist with the engine on and the trans in drive only
the drivers side front wheel spins, if I slow it down with my hand
then the passenger side starts to spin, should they not be turning
together? Also a while back it had a problem with the shift lock, it
was stuck in park and a mechanic had to do cut a wire or something to
fix this, could this have anything to do with the awd system. How does
this system operate. Thanks for any help.

 

[Carl 1 Lucky Texan]

My 95 subaru legacy's awd system is not working, it only has front
wheel drive. On a hoist with the engine on and the trans in drive only
the drivers side front wheel spins, if I slow it down with my hand
then the passenger side starts to spin, should they not be turning
together? Also a while back it had a problem with the shift lock, it
was stuck in park and a mechanic had to do cut a wire or something to
fix this, could this have anything to do with the awd system. How does
this system operate. Thanks for any help.

The front is an 'open' differential and seems to work normally. You
don't mention if you have a manual or auto-tranny.
here's some reading;

http://auto.howstuffworks.com/differential.htm
http://www.autozine.org/technical_school/traction/tech_traction_4wd_2.htm
http://www.mrtrally.com.au/performance/viscous_coupling.htm
http://www.endwrench.com/pdf/drivetrain/02Winter4EATTransOp.pdf

Carl

 

[mark]

The front is an 'open' differential and seems to work normally. You
don't mention if you have a manual or auto-tranny.
here's some reading;

http://auto.howstuffworks.com/diffe...ch.com/pdf/drivetrain/02Winter4EATTransOp.pdf

Carl

Well I did say it was stuck in park which means it had to be an
automatic. As for the open front differential,shouldn't both wheel be
spinning at the same speed until one encounters resistance?

 

[AS]

You may find a wheel turning while the other one is stopped due to
friction caused by the brake system, wheel bearings etc.

If the awd is not working, then you should be able to spin wheels when
flooring the gas pedal when stopped. This is easier to notice on a road
with sand or on grass.

Good luck

 

[Carl 1 Lucky Texan]

Well I did say it was stuck in park which means it had to be an
automatic. As for the open front differential,shouldn't both wheel be
spinning at the same speed until one encounters resistance?

You did mention the 'park' issue, sorry I missed that.
I THINK there may even have been some FWD only soobs from around '95 ?
But I assume your car was built as AWD. One thing, is there a light on
in the inst. cluster that says FWD? The 4EAT equipped soobs have an AWD
disable function utilized by placing a spare fuse into the FWD socket in
the fuse box under the hood. It is used under conditions where a flat
tire cause you to use a donut spare or other tire of odd size.

An open differential ,front or rear, will behave as you observed.
Indeed, with the engine off, spinning one side of the front axle should
cause the other to spin backwards. WRXs, STis and I think some Foresters
have LSD in the rear, spinning one side will likely cause the other side
to spin in the same direction. Maybe someone else here knows how the
4EAT behaves under the conditions you used - I don't.


Carl

 

[nobody >]

You did mention the 'park' issue, sorry I missed that.
I THINK there may even have been some FWD only soobs from around '95 ?
But I assume your car was built as AWD. One thing, is there a light on
in the inst. cluster that says FWD? The 4EAT equipped soobs have an AWD
disable function utilized by placing a spare fuse into the FWD socket in
the fuse box under the hood. It is used under conditions where a flat
tire cause you to use a donut spare or other tire of odd size.

An open differential ,front or rear, will behave as you observed.
Indeed, with the engine off, spinning one side of the front axle should
cause the other to spin backwards. WRXs, STis and I think some Foresters
have LSD in the rear, spinning one side will likely cause the other side
to spin in the same direction. Maybe someone else here knows how the
4EAT behaves under the conditions you used - I don't.

As far as the rear LSD, Outback Limiteds have it too. I can say for
certain that spinning one tire causes the other to spin the same
direction. I tried it while it was up on the lift for tires.

I didn't power up the car and put it in gear (4EAT) to see how the
front/rear differential acted tho...

 

[johninKY]

Original poster never mentioned any flashing dash lights. Bet only problem
is someone installed the FWD fuse.

 

[mark]

Original poster never mentioned any flashing dash lights. Bet only problem
is someone installed the FWD fuse.

I just checked over the car again, there is no empty fuse slot either
under the hood or under dash, all fuses are in place and acounted for
in the manuals diagram. The only fuse that has anything to do with the
drivetrain is one labeled "auto trans control module" . There is no
light on the dash saying FWD. In the "capacities" section in the
manual it lists automatic transmission fluid, AT differential oil, and
rear differential oil. Is this telling me it uses a center open
differential. There is no power at the rear wheels, on snow I can let
the front wheels spin for a minute and nothing happens at the rear. Is
it possible that what the manual calles AT differential oil is viscous
coupling fluid and mine could have leaked out dissabling the rear
output?

 

[Carl 1 Lucky Texan]

I just checked over the car again, there is no empty fuse slot either
under the hood or under dash, all fuses are in place and acounted for
in the manuals diagram. The only fuse that has anything to do with the
drivetrain is one labeled "auto trans control module" . There is no
light on the dash saying FWD. In the "capacities" section in the
manual it lists automatic transmission fluid, AT differential oil, and
rear differential oil. Is this telling me it uses a center open
differential. There is no power at the rear wheels, on snow I can let
the front wheels spin for a minute and nothing happens at the rear. Is
it possible that what the manual calles AT differential oil is viscous
coupling fluid and mine could have leaked out dissabling the rear
output?

First, check the manual under 'flats' or 'emergency spare'/whatever.
There should be instructions on using the spare fuse in the slot for FWD
in the fuse box under the hood.

If you have a rear differential then you obviuosly have an AWD vehicle
and, from your description, the 'wet clutch pack' or the 'duty solenoid
C' or other component is bad.

http://endwrench.com/main.php?smPID=PHP::article_detail.php&&RECID=247

Carl

 

[mark]

First, check the manual under 'flats' or 'emergency spare'/whatever.
There should be instructions on using the spare fuse in the slot for FWD
in the fuse box under the hood.

If you have a rear differential then you obviuosly have an AWD vehicle
and, from your description, the 'wet clutch pack' or the 'duty solenoid
C' or other component is bad.

http://endwrench.com/main.php?smPID=PHP::article_detail.php&&RECID=247

Carl

I checked the manual and found the slot for the FWD fuse. There is no
fuse there, I put one in to check and the dash light comes on and then
I removed it . The fluids in center differential and auto trans and
full. As I said before a mechanic disabled the shift lock mechanism,
now with engine off and key removed and foot not on brake the shifter
can be moved to any gear. Could this have anything to do with my
problem, it seemed the AWD stopped working right after he did this but
he insists it couldn't have anything to do with it. Is there any
electrical problems that would cause this? Could you tell me more
about the duty solenoid C? Thanks

 

[Carl 1 Lucky Texan]

I checked the manual and found the slot for the FWD fuse. There is no
fuse there, I put one in to check and the dash light comes on and then
I removed it . The fluids in center differential and auto trans and
full. As I said before a mechanic disabled the shift lock mechanism,
now with engine off and key removed and foot not on brake the shifter
can be moved to any gear. Could this have anything to do with my
problem, it seemed the AWD stopped working right after he did this but
he insists it couldn't have anything to do with it. Is there any
electrical problems that would cause this? Could you tell me more
about the duty solenoid C? Thanks

IIRC Duty Solenoid C opens a valve, relieving pressure to the clutch
pack in the tail of the tranny. It does this in response to a variable
square wave (variable duty cycle) sent by the TCU, such that the more it
is closed, the more torque is sent to the rear wheels. The FWD fuse, in
effect; causes the valve to stay open so no torque is applied to the
rear. So, either the valve is gimmed up or held open, the TCU or other
lectrical problem is causing the valve to stay open, or the clutch pack
is bad in some whay that force is not sent to the rear.

maybe someone else here knows of some tests.

Carl