stuck in AWD?

[nicconley]

Hi all, Im new here and have never owned a Subie before this one. Its a 91 Legacy wagon, and I bought it a month ago from the original owner. My issue is, everything worked perfectly until yesterday. I turned out of my driveway, and the drivetrain bound up (obviously in AWD). Its never done it before. I looked online and all I got was to insert fuse in FWD socket under hood. I did that, and all is fine. My question is, could that actuator solenoid go bad overnight (literally)? The PO (whom I know personally) said he's never ever had an issue with the AWD system. I followed a procedure for checking transfer hub codes (?) and got a 33 and 24. I think one of them is a speed sensor#2 code.
ANy help would be greatly appreciated. Thank you!!

[Alphius]

Sounds like you have what is called "torque bind". It is usually caused either by a failing Duty C solenoid (controls clutchpack lockup) or badly worn splines on the clutchpack carrier. Do you get the "Power" light on your dash flashing 16 times when you start the car?

The 33 and 24, are they current or historical codes? Check here on how to pull them for each and let us know what the current codes are:
http://www.surrealmirage.com/subaru/trans.html

If you do actually have code 24, your Duty C solenoid is probably bad. This is not too likely with the FWD fuse in since the fuse actually curing the torque bind is dependent on the Duty C actually working. If there are no current codes, it is possible that a fluid drain and refill will temporarily fix the torque binding.

[Legacy777]

Welcome to the BBS.

Does your speedometer work ok?

[nicconley]

speedo works fine. The power light does not flash when I start the car, and the car did not do this at all till the other day. I mean, literally overnight. I would think a scored clutch drum would get gradually worse. I havent had time to clear and recheck codes yet, but I will.
I assume that the system defaults to FWD and not AWD, correct? With the fuse in place, the car doesnt shudder or bind up at all. Thanks

[Alphius]

If the clutch drum is scored or the fluid is getting dirty it can either bind or not bind. So you have a pretty good chance of not having it bind on some corners and having it bind bad on some others. Honestly, with no current codes and the trans just starting to torque bind, you will probably be able to fix it by draining and refilling with new transmission fluid three times within a week to get as much of the old fluid out as possible.

The system with the FWD fuse out dynamically adjusts the torque split from 90/10 to 50/50 as you drive. It uses speed, throttle position and gear lever position to make it's choice, and continually adjusts between the two extremes as you drive in varying conditions.

With the FWD fuse in, it disables that control mechanism and always runs with the clutchplate unlocked.

[nicconley]

So, a friend of mine that works for Subaru told me that there was a service bulletin on some of them and they were changing the fluid and adding a friction modifier to eliminate ssome shudder. Any thoughts on this as well?

[Alphius]

Don't add any friction modifier. It will make the clutches and bands slip.

Your best bet without tearing into things is to drain and refill the fluid about three times, with driving in between. It should get better with each change, and by the third most of your old fluid will be out of the trans. Just use regular ATF, no additives or modifiers.

You still have not let us know if you have any current stored codes instead of historical ones.

[nicconley]

sorry its been so long, Ive been moving and havent worked on the Legacy. So, Ive driven it about 1000 miles, and I had to put the fuse in the FWD plug to get it to stop binding. Well, today, it started binding again and when I shut the key off and on, the power light did flash 16 times. If I have the fuse in, shouldnt the solenoid be disabled? Isnt that code for a faulty solenoid circuit? I havent changed fluid yet, but I will this weekend. I assume its just Dexron? Thanks!

[nicconley]

Also, when I shut the car off, it lurches backwards. Im assuming this is the clutchpack releasing when trans fluid pressure bleeds off. So, if the fuse is in, and it still binds, the clutch is causing it, right? No more DTCs, by the way, other than the 16 flashes upon startup. I just dont know whether to get rid of this thing or not. I cannot afford a $750 housing that seems to be what ails it. Thanks for the advice.

[Alphius]

16 flashes means that there is a stored code. Check the codes like we asked above and let us know what you get.

If the binding happens with the FWD fuse in, that means the Duty C solenoid is failing. It is possible that a few drains and fills of trans fluid will alleviate some of your issues. If not, you probably need a new Duty C.

[Legacy777]

16 flashes means that there is a stored code. Check the codes like we asked above and let us know what you get.

If the binding happens with the FWD fuse in, that means the Duty C solenoid is failing. It is possible that a few drains and fills of trans fluid will alleviate some of your issues. If not, you probably need a new Duty C.

Ditto what Alphius said. If the FWD fuse doesn't do anything to help, than the duty c solenoid is likely the culprit.

[nicconley]

So, there is a 24 code in the ECU. Im a bit confused now, so someone help me understand this. When the FWD fuse is installed, doesnt that disable the duty c solenoid? When it first started binding, it immediately went away when I put the fuse in. Then, a couple days ago, it suddenly started it again. With the fuse in. I changed the fluid twice, and the trans was just serviced, so the fluid looked brand new. Ive priced the solenoid at $174, and clutches at $420 from the Subaru stealership. Any aftermarket suppliers for this stuff?

[Alphius]

The fuse applies 12v directly to the solenoid all the time. With 12v applied, it should be fully disengaged. The reason you are seeing issues is because with the solenoid either broken or de-powered it allows full pressure to the AWD clutchpack. In other words, if the solenoid is failing, even the fuse being in will not alleviate your issues. You probably would be fine with a new Duty C solenoid. If you want to get out of it a little cheaper, I would suggest going to the junkyard and pulling a few of them out of wrecked cars with fairly low mileage. Any Phase1 4EAT will have the correct solenoid, I believe that is '90 through '98 or '99 in Legacys.

[nicconley]

So, an update. The only code that came up was the 24 code. I found the part for $104 at the subaru dealer my friend works at, but I cant get it for a couple weeks. So, out of the blue last week, it quits binding completely. I drove in circles, did figure 8s, and not binding. The power light quit flashing on startup. Then, about an hour ago, I got in it to go to lunch, and now its doing it again. Would this solenoid be on again/off again?

[Legacy777]

With an intermittant issue......I would maybe lean more towards a shorted/disconnected wire or something in the transmission or even external to the trans. The best advice I can give is to disconnect the trans connector plug and check the resistance of the solenoid from there. If it checks out ok, then you've likely got a wiring issue somewhere in the chassis harness. If the solenoid doesn't check out ok, then the solenoid may be bad and/or there may be a wiring issue internal to the trans.

Until you do some further testing, it's hard to say for sure.

These scans should help.

http://main.experiencetherave.com/subar ... _diag1.jpg
http://main.experiencetherave.com/subar ... _diag2.jpg