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Discussion Starter #43
So... while I wait (and wait and wait, it's taking sooooo long) for the valve body to show up in the mail I've been thinking... and wondering.

IF the AWD solenoid is toast is there any real danger in driving the car? Will it simply be a FWD awesome wagon or can I do further damage to the rest of the valve body/transmission? I have a camping trip coming up and would HATE to have to pack everything into my wife's Nissan Juke. Plus, I don't even know if it CAN tow the trailer we just picked up.

If anyone is still listening, I'd be curious to know your thoughts. Thanks.
 

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I don't know, so I'm only thinking aloud here....

Usually when a critical system component fails the manufacturer has built in a default fail safe mode to allow you to limp along. In the case of a failing AWD solenoid one might think the fail safe would be to permanently release the viscous couple to only send power to the front wheels. Others can probably confirm. But if that is NOT the fail safe then it sounds like you might put some premature wear on the drive train. From this link:

"The first one is the AWD duty solenoid for applying and releasing the viscous couple when needed. The system needs to allow slip in the clutch when the front and rear tires are rotating at different speeds. This is usually only on turns."
 

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Discussion Starter #45
It would be ideal if the car was 'just' front wheel drive, for now, but I fear there's more to it.

And it sounds like there almost certainly is. Even not being certain is reason to be cautious. And not take a trip into the wilds with the trailer. Thanks for keeping my head on straight, OBDad.

Cheers.
 

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the manufacturer has built in a default fail safe mode to allow you to limp along. In the case of a failing AWD solenoid one might think the fail safe would be to permanently release the viscous couple to only send power to the front wheels.
That depends on the nature of the fault.

If the wire to the solenoid, or the solenoid itself, is open circuit, or the wire is shorted to ground, then the control signal can't reach the solenoid. It remains in it's default mechanical position, and that prevents significant hydraulic pressure from reaching the transfer clutch piston; no pressure, no engagement, and the car is essentially FWD. However, what effect a short to ground could have on the TCM control circuit over time isn't certain. (There could be some form of current limiter that will prevent damage to the TCM.)

But that code could also be caused by a short between the wire to the solenoid and another wire in the harness that has voltage on it. (This is relatively rare, but is still a consideration.) That could lead to the solenoid being continuously activated, leading to an engaged clutch. If the clutch is fully engaged, there could be torque bind symtoms, but that would depend in part on the voltage and current being supplied to the solenoid. (Being a contact connection, the actual current could be limited.) The solenoid might be allowing the clutch to be engaged to a fair degree continuously, whereas it's normally modulated depending on the driving conditions. That might not result in apparent torque bind symptoms, but it could lead to additional wear on the clutch. In this case, the TCM has no way to override the short, so there's no functional failsafe.

If it was just some local driving around town, it probably wouldn't be a serious factor. But without knowing the actual nature of the fault, going on a long trip, and, towing a trailer, is probably not a good idea if you're also really serious about keeping the car a long time.
 

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Discussion Starter #48
I wasn't really thinking about towing the trailer unless I could determine (with some certainty) that it was safe. But, yeah, good points.

I am hoping to keep the car for a LONG time, so I won't do anything to kill it. Hopefully.

Cheers.
 

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Discussion Starter #49
So... excellent news.

The rebuilt valve body arrived in the mail on Wednesday, by Thursday at lunch the transmission shop had swapped it out and had everything up and running. Took it out last night for a spin and again today for a slightly longer test. No issues. No lights. No noise. All good.
And the best part is that the shop only charged me $400. For a fluid flush and fill and to put in the new valve body. I'll gladly pay that. Especially when the valve body alone would have cost me $1400+ tax from Subaru.

Thanks to everyone who helped with this. I appreciate it. Now, to get ready for camping with the trailer.

Cheers.
 
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