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95 legacy 4eat, awd not working!


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ok its just weird...

 

i installed the center diff switch to make sure the AWD is working, and even with the switch, and locked it does not go into AWD.

 

could it be that the clutch packs on the rear of the tranny are fried?

 

hmmm, would it give me a code or something?

 

i dont get it

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really, it doesn't work with the Duty C solenoid switch? that was going to be my recommendation. did you find the correct wire for it?

 

i would verify...just to make sure, that is an AWD transmission actually in the vehicle. most wouldn't know this, but FWD and AWD trans are nearly interchangeable actually. unlikely but takes 2 seconds to check. while you look under the vehicle make sure the rear driveshaft is in place, it could have been removed for defective ujoints...another stretch, but takes 2 seconds to look at. they can be removed...but would have to have severe torque bind (welded transfer clutches) or have the Duty C Solenoid wire cut somewhere...which should make the transmission light flash. either way - check for AWD and make sure the driveshaft wasn't removed.

 

others will chime in with suggestions but if it comes to it, you can swap the rear extension housing (has all the transfer clutches and stuff in it for the 4WD) with another one without dropping the transmission. there are some good threads on here about doing that, check those out if you get to that point.

 

I think they were all AWD in '95 right,
there were FWD Legacy's up to 96...even a couple hundred in 97 though you won't see them listed as such most places (like parts stores).
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really, it doesn't work with the Duty C solenoid switch? that was going to be my recommendation. did you find the correct wire for it?

 

i would verify...just to make sure, that is an AWD transmission actually in the vehicle. most wouldn't know this, but FWD and AWD trans are nearly interchangeable actually. unlikely but takes 2 seconds to check. while you look under the vehicle make sure the rear driveshaft is in place, it could have been removed for defective ujoints...another stretch, but takes 2 seconds to look at. they can be removed...but would have to have severe torque bind (welded transfer clutches) or have the Duty C Solenoid wire cut somewhere...which should make the transmission light flash. either way - check for AWD and make sure the driveshaft wasn't removed.

 

others will chime in with suggestions but if it comes to it, you can swap the rear extension housing (has all the transfer clutches and stuff in it for the 4WD) with another one without dropping the transmission. there are some good threads on here about doing that, check those out if you get to that point.

 

there were FWD Legacy's up to 96...even a couple hundred in 97 though you won't see them listed as such most places (like parts stores).

 

 

hey grossgary

 

yeah the vehicle is an awd i was under it yesterday, the drive shaft is there and the u joint in in good condition. I cheked the VSS1 on the rear of the tranny, cleaned and all, now i am suspecting that can be 3 things, a bad Vss1, a bad TCU and most likely the rear extension housing. now couldit be a bad TCU?,the weird thing is that when installed the switch this morning (yes correct wire), i started the car with the switch on the light did blinbk as it should, then i turned the switch off and started the car again it did not didnt blink as it should with the switch. Now, i would have some sort of torque bind if the rear extension was bad right? so it makes me thnk is a TCU, i just came back from the JY and got a new TCU for free, i'll swap that one in and see... :-\

 

Edit: btw the tranny swifts great, is the best 4eat i've ever had, no delays on shifting or putting reverse or drive

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it could be the TCU but i highly doubt it.

 

when you put the FWD fuse in - does the FWD light come on in the dash? you should see it.

 

i would make sure the speed sensor is giving some kind of input, but i'm not well versed in checking or testing those. come to think of it i bet the FSM has a good trouble shooting guide in the transmission section for "AWD not working properly" and will certainly include details on the VSS - how it works, what it does and how to test it.

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Im gonna say I think the high pressure line that carrys presure to the rear extension may have come loose or is leaking. If you dont' get mad torque bind with the C solenoid switch activated(which actually means switch in the "OFF" position/no continuity/ no power to the solenoid.) Then you have no pressure to the clutches. Even worn clutches will grab with full pressure.

 

You can test it, or have it tested, by removing the small plug on the rear, drivers side of the trans, towards the top. Install a line pressure gauge there, and take a reading. Should be 7-11 PSI at idle in gear. 104-114 PSI at stall RPM in gear.

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it could be the TCU but i highly doubt it.

 

when you put the FWD fuse in - does the FWD light come on in the dash? you should see it.

 

i would make sure the speed sensor is giving some kind of input, but i'm not well versed in checking or testing those. come to think of it i bet the FSM has a good trouble shooting guide in the transmission section for "AWD not working properly" and will certainly include details on the VSS - how it works, what it does and how to test it.

 

 

yeah i just got done getting the tcu swap.. and nothing

 

yeah the light comes on when i put the fuse in there, i'm totally speechless, i cant find the problem

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Im gonna say I think the high pressure line that carrys presure to the rear extension may have come loose or is leaking. If you dont' get mad torque bind with the C solenoid switch activated(which actually means switch in the "OFF" position/no continuity/ no power to the solenoid.) Then you have no pressure to the clutches. Even worn clutches will grab with full pressure.

 

You can test it, or have it tested, by removing the small plug on the rear, drivers side of the trans, towards the top. Install a line pressure gauge there, and take a reading. Should be 7-11 PSI at idle in gear. 104-114 PSI at stall RPM in gear.

 

 

is that an external line? i have no leaks

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is that an external line? i have no leaks

 

No it's internal. It's a metal tube Between the Extension and the main case. It carrys line pressure to the rear extension. It can come loose inside and leak. Like I sadi, you can test and see if line pressure is making it back there by using a pressure gauge installed at the plug I told you of. It's got a square head, it's about 3/8" in diameter, and is on the tail of the extension housing. Basically opposite the rear speed sensor.

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there's an end wrench article about checking the front and rear final drive ratios in automatics. it coulkd be used in this case to check the AWD lock up.

 

you put the car on jack stands, unplug the wire harness to the trans, and start the car in neutral. this will lock the AWD transfer clutch. and as you turn the rear wheel by hand the front wheel will match it turn for turn. (MAYBE IT'S JUST ONE SIDE OF THE CAR ON JACK STANDS?? BETTER READ THE ARTICLE.) if the wheels don't turn the same, or don't turn at all then there is something missing in the transfer clutch. maybe it had torque bind and someone removed the clutch plates.

 

i can't think of another explanation for it not locking up. this AWD unit uses fluid pressure to dis-engage the rear wheels, lack of pressure would equal locked. EDIT Correction: the duty c when activated releases pressure from the transfer clutch and allows the rear wheels to slip. the FWD fuse powers the duty c all the time making the car FWD only.

 

unless it's one of thoses wierd JDM autos that work backwards.......

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i can't think of another explanation for it not locking up. this AWD unit uses fluid pressure to dis-engage the rear wheels, lack of pressure would equal locked.

 

Sorry, you've got it backwards. The solenoid drains pressure from the transfer clutch to keep it from fully locking, and allows for a "differential" effect. When the solenoid is disconnected, or not powered, the drain is closed. This causes full line pressure goes to the transfer clutch, locking the rear clutch pack.(there is a mechanical, spring loaded drain that prevents overpresure, but it only dumps when transfer pressure begins to exceed pilot pressure)

 

Bottom line, if he has a loose extension tune, no pressure reaches the clutches, thus no AWD.

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Sorry, you've got it backwards. The solenoid drains pressure from the transfer clutch to keep it from fully locking, and allows for a "differential" effect. When the solenoid is disconnected, or not powered, the drain is closed. This causes full line pressure goes to the transfer clutch, locking the rear clutch pack.(there is a mechanical, spring loaded drain that prevents overpresure, but it only dumps when transfer pressure begins to exceed pilot pressure)

 

Bottom line, if he has a loose extension tune, no pressure reaches the clutches, thus no AWD.

i've been wrong before, but this article seems to me to indicat that without electrical in put from the tcu, the AWD will lock.

 

http://endwrench.com/images/pdfs/CorrectInfo.pdf

 

am i reading it wrong? wait, i get it, i'm wrong about how the AWD works. never mind.

 

seems you could still use this procedure to check if the AWD will in fact lock. wouldn't this be the same as the 'swicth'? regardless, if the wheels don't turn together, there is something wrong, but you already knew that.

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i've been wrong before, but this article seems to me to indicat that without electrical in put from the tcu, the AWD will lock.

 

http://endwrench.com/images/pdfs/CorrectInfo.pdf

 

am i reading it wrong?

 

That is correct. But what you are missing is that the electrical input DRAINS the pressure, not applies it. So without the drain, full pressure i applied to the clucthes. But if the pressure isn't making it to the rear end (loose or leaking tube inside) then there is no pressure to control.

 

The only way to know is to either test the transfer pressure at the plug I mentioned, or remove the extension and look inside. If you just open her up, and the tube is fine, then you won't know anything. So I would highly recommend taking it to a trans shop and telling them SPECIFICALLY to test the transfer pressure. Just start there, don't let them try to sell you a new trans or rebuild yours,....yet.

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is it normal for ATF to drip out of the Vss1 hole? i removed it and atf started dripping out

 

 

Well, the VSS gear is lubricated, so I can see it dripping a bit from around the hole. But.... it shouldn't be ATF, should be gear oil(front half of subie auto trans is the differential, seperate lube, sealed chambers) And it shouldn't keep draining from there, if it does, you're a tad overfull in the diff.

 

Have you taken it to a dealer and asked them to extract the codes form the TCU? are you getting any blinking of the AT temp or POWER lights?

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