The classic solenoid duty c question...

[SplitSecondDsm]

I know this is a common topic asked, but I've been searching and I really need to fix my subaru before class starts again so I figured I'd throw this up while I was doing some research.

So yeah, my subaru has gradually become fwd over the last month, and I'm wondering if it is this transfercase solenoid I keep hearing about. The car does not power the rear wheels, there is no flashing of the power light so I think that rules out the tcu, which scares me into thinking maybe the clutch packs are screwed, but hopefully it's just the solenoid though. There is no "toque binding" that I have read about, and I threw a fuse in the fwd holder just to shut off the rear until I sort this out. The transmission/tcase fluid is clean, drained and new filter 10k ago with synthetic atf and a bottle of lucas transfix, no shavings whatsoever in the transmission pan.

Any more info/experience on this issue and where I can purchase this solenoid? Is there a way to test it? Thanks.

[1-3-2-4]

well first of all how long have you been riding around with the fuse in for FWD? As it states in the manual it's not meant to be used long term.

[Huffer]

So yeah, my subaru has gradually become fwd over the last month,

Please explain this in more detail.

Also, when the DutyC fails, the car is permanently locked in 50/50 torque mode, same as if you were driving in D3, D2, or D1. D4 (or D) is the only mode where the car is 90/10 torque split until the front wheels start to slip, then torque is directed to the rear.

http://www.google.com/search?q=duty+c+s ... US266US266 (http://www.google.com/search?q=duty+c+solenoid&sourceid=navclient-ff&ie=UTF-8&rlz=1B3GGGL_enUS266US266)

[SplitSecondDsm]

fwd fuse has been driven with for 10 miles, then I figured I'd park it until I figured it out, I only threw it in there because I was more afraid of ruining the tcase. I felt no symptoms of torque binding around corners with the fuse out of the car, so I'm thinking that rules out a physically damaged tcase. I also realize that the solenoid locks 50/50 torque when it fails, but there is no flashing of the power light when the car first starts, and no codes from the ecu, so I think the tcu is working fine.

With the car in regular 90/10 mode, there is no power to the rear wheels. Fluids are clean and new, filters are good, car runs great. This has got to be electrical.

[Huffer]

Waitasec, how do you know the rear wheels aren't turning under load? Did you put it up on a lift and run it in D3 mode?

[SplitSecondDsm]

false alarm, my father had gotten the car stuck on a big patch of ice and I took his word that the rear wheels weren't spinning, I pulled the fuse out, put the car on some snow, and it pulled right out of it, works fine. Thanks for the input!

[1-3-2-4]

Ah.. the power of having front and rear open diffs..

[SplitSecondDsm]

haha yeah, if it was a worn out viscous coupler on a dsm, you could just weld that sucker and deal with 50/50 torque, but not with a 4EAT haha

[SplitSecondDsm]

Someone posted a good readup on how to check the tcu for codes on ccdsm.net, figured I'd share...

to check for TCU codes do this:

The "Power" light indicates transmission codes. Long blinks = 10, short blinks = 1. In other words, two long and two short blinks is a code 22. One long and one short is code 11. The following self diagnosis will show any fault codes for the transmission.

The most common trouble code is "11" and is almost always caused by a faulty transmission resistor located between the battery and fender.

To perform the self diagnosis test for EXISTING problems:

Warm up engine by driving at speeds greater than 12mph.
Stop vehicle and turn ignition switch OFF.
Turn ignition switch ON and make sure POWER indicator lamp comes on.
Turn ignition switch OFF.
Move selector lever to D and turn manual switch ON.
Turn ignition switch ON.
Move selector lever to "3" and turn manual switch OFF.
Move selector level to "2" and turn manual switch ON.
Move selector lever to "1" and turn manual switch OFF.
Partially depress accelerator pedal (to turn idle switch off).
Check code as displayed on POWER light. Blinking once every 1/4sec is normal.


To perform the self diagnosis test for PREVIOUS problems:

Warm up engine by driving at speeds greater than 12mph.
Stop vehicle and turn ignition switch OFF.
Turn ignition switch ON and make sure POWER indicator lamp comes on.
Turn ignition switch OFF.
Move selector lever to "1" and turn manual switch ON.
Turn ignition switch ON.
Move selector lever to "2" and turn manual switch OFF.
Move selector lever to "3" and turn manual switch ON.
Move selector lever to "D" and turn manual switch OFF.
Partially depress accelerator pedal (to turn idle switch off).
Check code as displayed on POWER light. Blinking once every 1/4sec is normal.

List of TCU Trouble Codes
Trouble Code Item
11 Duty solenoid A
12 Duty solenoid B
13 Shift solenoid 3
14 Shift solenoid 2
15 Shift solenoid 1
21 ATF temp sensor
22 Atmospheric sensor
23 Engine revolution signal
24 Duty solenoid C
31 Throttle sensor
32 Vehicle speed sensor 1
33 Vehicle speed sensor 2

[ScaryFatKidGT]

Ah.. the power of having front and rear open diffs..

i know i want limited slip ones so bad i could go threw so much more snow gosh *wants a STi*

[ScaryFatKidGT]

So yeah, my subaru has gradually become fwd over the last month,

Please explain this in more detail.

Also, when the DutyC fails, the car is permanently locked in 50/50 torque mode, same as if you were driving in D3, D2, or D1. D4 (or D) is the only mode where the car is 90/10 torque split until the front wheels start to slip, then torque is directed to the rear.

http://www.google.com/search?q=duty+c+s ... US266US266 (http://www.google.com/search?q=duty+c+solenoid&sourceid=navclient-ff&ie=UTF-8&rlz=1B3GGGL_enUS266US266)


:smt017 could this be made to purposely fail??? and get 50/50 in drive with out adverse affects besides less gas milage???

or should i just stick my 4eat in D3 and be happy?

[1-3-2-4]

So yeah, my subaru has gradually become fwd over the last month,

Please explain this in more detail.

Also, when the DutyC fails, the car is permanently locked in 50/50 torque mode, same as if you were driving in D3, D2, or D1. D4 (or D) is the only mode where the car is 90/10 torque split until the front wheels start to slip, then torque is directed to the rear.

http://www.google.com/search?q=duty+c+s ... US266US266 (http://www.google.com/search?q=duty+c+solenoid&sourceid=navclient-ff&ie=UTF-8&rlz=1B3GGGL_enUS266US266)


:smt017 could this be made to purposely fail??? and get 50/50 in drive with out adverse affects besides less gas milage???

or should i just stick my 4eat in D3 and be happy?

no because driving in 50/50 all the time for the auto is not good.. and not good for on the highway since it wont go to 4th gear.

[ScaryFatKidGT]

y isnt it good for the auto?

well i would put it back into drive to drop the rpm's over like 55mph

[decke48]

its not good because the rear wheel need to be able to go slower when cornering so it doesnt bind.
D3,2,1 allow the center diff to lock (50/50split) only when all wheel speeds are the same. if one wheel goes slower it changes the split to 60/40 to allow cornering without binding

[ScaryFatKidGT]

ohhhhh? so hows the manual work

[decke48]

the manual has a viscous clutch to allow some freedom to overcome the difference in wheel speed

[ScaryFatKidGT]

ohhhh! i knew that i guess i didnt relize the autos didnt have a viscous clutch

[SplitSecondDsm]

I know a ton of people weld the center diff on dsm's to achieve 50/50 torque vs. a stock viscous 60/40, but primarily for the power holding ability. The reason you can do this on a manual transmission 4wd vs. the 4eat is because there are clutch packs in the tcase with a 4eat that will wear out from binding around corners vs. a welded diff in a manual just breaking the tires loose around corners. A welded diff is annoying on the street though, and I would much rather prefer a 4 spider diff that will hold the power just fine until 600 awhp.

[SplitSecondDsm]

Problem still exists, I believe the clutch packs in the transfer case are wasted. Can anyone tell me where I can find either a rebuild kit or a total transfer case assembly for a phase 1 4EAT transmission? Thanks in advance.

[Huffer]

Problem still exists, I believe the clutch packs in the transfer case are wasted. Can anyone tell me where I can find either a rebuild kit or a total transfer case assembly for a phase 1 4EAT transmission? Thanks in advance.

If you are getting torque bind, then you can try draining and refilling the ATF with regular ATF and throwing in a bottle of Lubegard ATF Protectant.

I've personally used Lubegard ATF Proc. on 3 subarus that were experiencing early, moderate and SEVERE torque bind. The Lubegard was good enough to bring the clutchpacks back from death. In the last one I did, I took a 96GT that had been torque bound for 1 year (and still driven that way!) and within 50miles it was gone.

[SplitSecondDsm]

The thing is there is 0 torque bind because the awd is intermittent at best, even in locked 50/50 1st gear mode, the front just power with the occasional push then let go from the rear wheels. There are no codes, so the solenoid is fine, it has to be mechanical I'm thinking.

I emailed IPT about a tcase only overhaul kit, they said they could put one together for me for $80, so I'll probably rebuild the clutch packs and while it is out with the transmission dropped I'll probably throw in a new solenoid for the future.