how long can I drive my AWD in FWD mode?

dacecil · Post by **dacecil** » Wed Aug 30, 2006 5:35 am

I am still working on my vibration problem, and came across the FWD connector under the hood. Some research indicates that I can defeat the AWD system by inserting a fuse in there.

Can I drive like this at any speed indefinitely? I need to take a trip in this car on Thursday and want to know if defeating the AWD will have any ill effect.

Thanks
Dale

Splinter · Post by **Splinter** » Wed Aug 30, 2006 6:15 am

You'll burn out the Duty C solenoid if its any significant distance (I wouldnt drive more than 30 miles at low speed that way)

Manarius · Post by **Manarius** » Wed Aug 30, 2006 1:15 pm

Splinter wrote:You'll burn out the Duty C solenoid if its any significant distance (I wouldnt drive more than 30 miles at low speed that way)

Ditto. The FWD fuse it not meant for regular driving. It's meant for diagnostic purposes only.

monty's legacy · Post by **monty's legacy** » Sat Sep 30, 2006 2:36 am

haha I drove on a fwd fuse for almost two years on the adivce of subaru tech. it was either that or rear diff problems. but the car ran mint for that whole time.

quicklook · Post by **quicklook** » Sat Sep 30, 2006 3:25 am

so who is right?

Manarius · Post by **Manarius** » Sat Sep 30, 2006 6:31 am

quicklook wrote:so who is right?

Luck of the draw I guess. The Owner's Manual clearly states that it's for diagnostic testing only. However, some people have gone many months or years with the fuse in. I personally wouldn't want to test it because replacing the solenoid is a pita.

Bheinen74 · Post by **Bheinen74** » Sat Sep 30, 2006 7:28 am

It is for diagnostic purposes only.

When the fuse is in, there is no pressure on the rear clutch pack of the tranny (here is where the duty solenoid comes into the picture), which means no output to rear driveshaft.

WHAT THIS MEANS IS WITHOUT PRESSURE, the FRICTION CLUTCH DISKS are rubbing and sliding/slipping as the rear wheels are turning the driveshaft, with slippage instead of contant pressure. This slippage without pressure lockup RUINS the clutch packs REAL quick, resulting in a major teardown of that center diff if you ever want AWD to work again.

Unless you know the center diff is already RUINED, NEVER drive the car with the fuse in, IT DOES DAMAGE THE CENTER DIFF CLUTCHES and REAL quick. thanks Anyone whoe drives around with the fuse in is stupid......ie do you drive around with the parking brake set on too, or would you drive the car around without oil in it..etc etc .>>>>

entirelyturbo · Post by **entirelyturbo** » Sun Oct 01, 2006 5:11 am

Yes, it will wear out the Duty C solenoid prematurely, but it will not destroy the clutch packs. I know people who have run, and continue to run, the FWD fuse for years.

Bheinen74 · Post by **Bheinen74** » Sun Oct 01, 2006 7:43 am

subyluvr2212 wrote:Yes, it will wear out the Duty C solenoid prematurely, but it will not destroy the clutch packs. I know people who have run, and continue to run, the FWD fuse for years.

hey subyluvr2212, have you ever torn down the center diff assembly? please answer........
here.:
http://new.photos.yahoo.com/bheinen/alb ... 8903#page1

if you have, then i "might" believe your statement here.
seee picts first.

entirelyturbo · Post by **entirelyturbo** » Sun Oct 01, 2006 4:19 pm

Nope, never torn down any transmission.

And the clutch packs in your pictures, they got the way they were from someone running the FWD fuse for a long period of time?

Bheinen74 · Post by **Bheinen74** » Sun Oct 01, 2006 5:41 pm

I don't know, I bought the car with a bad tranny (to repair), and when we tore it apart, the Duty Solenoid was not working at that time. Anyways, it has been repaired with new clutch pack and a good duty solenoid and is like brand new now.

monty's legacy · Post by **monty's legacy** » Sun Oct 01, 2006 7:44 pm

Bheinen74 wrote:It is for diagnostic purposes only.

When the fuse is in, there is no pressure on the rear clutch pack of the tranny (here is where the duty solenoid comes into the picture), which means no output to rear driveshaft.

WHAT THIS MEANS IS WITHOUT PRESSURE, the FRICTION CLUTCH DISKS are rubbing and sliding/slipping as the rear wheels are turning the driveshaft, with slippage instead of contant pressure. This slippage without pressure lockup RUINS the clutch packs REAL quick, resulting in a major teardown of that center diff if you ever want AWD to work again.

Unless you know the center diff is already RUINED, NEVER drive the car with the fuse in, IT DOES DAMAGE THE CENTER DIFF CLUTCHES and REAL quick. thanks Anyone whoe drives around with the fuse in is stupid......ie do you drive around with the parking brake set on too, or would you drive the car around without oil in it..etc etc .>>>>

the only reason I had done it was, I was told diffs were already crap, and basically was told it was a crap shoot. It never failed me, but was told it could, fortunately never went on me. So I had to go with it, I think it went for 20K after that and no idea what the new owner of the car is doing with it

entirelyturbo · Post by **entirelyturbo** » Mon Oct 02, 2006 4:27 am

Bheinen74 wrote:I don't know, I bought the car with a bad tranny (to repair), and when we tore it apart, the Duty Solenoid was not working at that time. Anyways, it has been repaired with new clutch pack and a good duty solenoid and is like brand new now.

Okay, so maybe the tires were not rotated on this transmission, and the clutch packs got cooked. Then, someone told them about the FWD fuse trick, and they put it in the car to stop the torque bind, and burned out the Duty C solenoid...

shemoves · Post by **shemoves** » Thu Oct 26, 2006 12:31 am

I think I know what fuse you are talking about. Says 'FWD' on it, passenger side, near fire wall, correct? If so, what should it look like if I want it to be AWD?

Fishy · Post by **Fishy** » Thu Oct 26, 2006 12:53 pm

shemoves wrote:I think I know what fuse you are talking about. Says 'FWD' on it, passenger side, near fire wall, correct? If so, what should it look like if I want it to be AWD?

That is the infamous FWD Fuse socket. If you want AWD you want that fuse socket to be empty.

no FWD fuse = awd fun

shemoves · Post by **shemoves** » Thu Oct 26, 2006 7:46 pm

I saw the cover with "FWD" on it and thought it was a special fuse (didn't know it had a cover) and thought...ah crap, I've been in FWD this whole time.

On a side note...the 4eat's are 90% front/10% rear...it's like they did it just so they could say it was AWD

entirelyturbo · Post by **entirelyturbo** » Fri Oct 27, 2006 1:48 am

The split changes though, shemoves. In fact, the time it spends in 90/10 is rather small.

shemoves · Post by **shemoves** » Fri Oct 27, 2006 2:41 am

care to explain a bit? (learning more and more about this subaru AWD

)

entirelyturbo · Post by **entirelyturbo** » Fri Oct 27, 2006 3:30 am

Without getting into too much detail, the automatic AWD system does really "transfer power from the wheels that slip to the wheels that grip."

Do you have a 4EAT shemoves? If so, next time it's raining outside, take off hard from a stoplight. Power-braking it would be even better. Pay attention to what happens at the instant your car takes off. You should feel the front wheels slip for a blink of an eye, that's it being in 90/10 mode. But when the AWD senses that the front wheels are spinning, it will start sending more power to the back wheels, up to an even 50/50 split.

It actually does this a lot, even in the dry. You will just notice it more in the wet.

shemoves · Post by **shemoves** » Fri Oct 27, 2006 3:51 am

very cool. That is actually exactly what I wanted to know...I was wondering what the split 'range' was.

gt tankie · Post by **gt tankie** » Sat Oct 28, 2006 5:48 am

*cough cough ahem*

the duty c failed in mine and I ended up stuck in front wheel drive by default.
I ran with it like that for 65000 kms with no ill effect.
If your tyres are all the same size then movement between the plates in the clutch pack will be minimal ( unless you indulge in a lot of wheel spin)
I removed the trans extension housing and replaced duty c and its valve body and measured the drive and driven plates-reassembled it all and its worked fine since.

ECU monitors front and rear shaft speed via vss1 and vss2 and constantly compares them to each other. Should one differ too much from the other the ecu changes the duty c duty cycle in an effort to match the shaft speeds effectively controlling distribution of drive. ECU also monitors TPS voltage and varies duty c duty cycle i.e. idle 90/10 split - foot flat 50/50 split. The futher the foot goes down, the more drive goes to the rear.
You can hear the duty c solenoid buzzing from the case if you set igntion to run (engine off), place trans in drive and progressively press the gas pedal.

Mine failed due to fine metal particle build up sticking to the iron core of the soleniod and binding it up. The 4eat has a large magnet in the sump to collect ferrous metals. This became saturated with metal in mine so the metal circulated to the other magnets in the trans these being SOLENOIDS. When they are energized they suck this crap in and hold it resulting in eventual failure (clean that sump mag once in while!!)

Did ALOT of research on this one before I fixed it.

Back in my box now.

Gary

Soarer · Post by **Soarer** » Sun Mar 04, 2007 11:36 pm

damn Gary, you know your $hit

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how long can I drive my AWD in FWD mode?

how long can I drive my AWD in FWD mode?