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#16
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Well hey now our trannies are more similar. I put a fuse instead of a switch because I am only going to have the 50/50 split when it snows. And in answer to your question I would rather not get stuck in the snow. Many people on here say if the cars in FWD all the time the diff will blow. Now you say if its in 4WD the diff will blow. Well you know what good I hope it blows! As my car was (before I just did this) the car wouldnt even move in the snow unless I put it in 2nd and barely gave it any gas. If I wanted to change lanes it was nearly impossible to not slide. The car as I said really sucks in just FWD when its supposed to be AWD. So now when I remove the fuse the 50/50 split works. I believe either my TCU is always sending power to the solenoid making it FWD. I dont know if the TCU is bad or one of the sensors that communicates with the TCU. I have no codes on the TCU. If anyone else tells me that when the solenoid fails the car becomes FWD I would have to say you mean the TCU fails because unless your talking about the solenoid failing by sticking in the closed position it cant be true. Also If you look at the info in LEE's PDF file it show the connectors wrong it counts from 8-1 when it should count from 1-8 as 3 in that order is an empty spot no wire. Although a few pages down it shows the voltage for that wire with the FWD fuse in with power. Not without. And normal operation were the solenoid would be making the AWD work is less voltage less power. No power equals 50/50 split 100% fluid to transfer clutch!! SO BLAH BLAH BLAH I WIN
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1989 Subaru XT6 130k 1992 Subaru SVX 120k 1993 Ford Probe 30mpg 213k 1989 Subaru XT6 150k All good and running Last edited by spinn360; 03-19-2006 at 07:21 PM. |
#17
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In the event of failure Sol C closes, the clutches are applied and over a short period of time provided the clutch packs are good, binding will deteriorate the differential, eventually breaking it, causing a FWD situation that may lead to the loss of the entire drivetrain given the right circumstances. --- I think given the conditions you are explaining and the nonexistent history of TCU faliures either your center diff is chunking or your Sol C is sticking in a full or partly open position. It might be obstructed. I think if you wire a switch to override the TCU and force constant 50/50 AWD you will undoubtedly blow a diff, but if you are just going to use it in slippery conditions by all means go for it. This might be an easy way to help pinpoint the trouble.
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"That which can be asserted without evidence can be dismissed without evidence." '92 Dark Teal SVX LS-L, >146,000m 3 pedals, 5 speeds., restoration underway. 2012 Honda Insight, slow but cute. |
#18
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You can never achieve a 50/50 split on a US 4EAT...the BEST you can get is a 60/40 split, as even completely closed the transfer clutches WILL slip some...just my thought on the matter...
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Huck Subaru Ambassador 92 SVX LS-Tour Magnaflow Exhaust, 5-Spd-AWD 88 XT6 AWD 5-Speed "Bride of FrankenWedge" 15 Impreza Premium Sedan 15 Crosstrek XV 5-Speed My 5-Speed "How-To" Write-up 1976 Pontiac Firebird Formula Current Count of Subaru's Owned.... "70" |
#19
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The missing link.
You are overlooking the section between the C solenoid and the transfer clutch. The C solenoid does not control the transfer clutch directly. The C solenoid controls the Pilot pressure, which operates the transfer valve, that applies line pressure to the clutch.
As you say the rear does kick in with a delayed action, binding is felt. These are the symptoms of a sticking transfer valve, not a C solenoid problem. Switching the C solenoid, won't fix the problem, as it is doing what it is suppose to. The transfer valve is not reacting to the changes in the Pilot pressure. The rear of the trans has to come off to replace the C solenoid/transfer valve assemble, shown below. Harvey.
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One Arm Bloke. Tell it like it is! 95 Lsi. Bordeaux Pearl, Aust. RHD.149,000Kls Subaru BBS wheels. 97 Liberty GX Auto sedan. 320,000Kls. 04 Liberty 30R Auto Premium. 92.000kls. |
#20
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Harvey has spoken!
/thread The pic helps a lot. I have never seen the thing and now I can put words to picture. Now I can avoid going back and forth in my explanations of things I don't completely understand, but I did have a feeling it was definitely a sticking something.
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"That which can be asserted without evidence can be dismissed without evidence." '92 Dark Teal SVX LS-L, >146,000m 3 pedals, 5 speeds., restoration underway. 2012 Honda Insight, slow but cute. |
#21
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Making it clearer.
Just to make the previous post clearer. This is the way the hydraulic pressure, to the transfer clutch is controlled.
The red line is the line pressure, that is fed to the transfer valve, and the Pilot valve. The Pilot valve regulates a constant pressure, that the C Solenoid controls, to apply a pressure (yellow) to the end of the transfer spool valve. This Pilot pressure pushes the spool valve across to allow the line pressure to flow to the transfer clutch (blue). The C solenoid controls the Pilot pressure by bleeding it off, so that the transfer spool does not move across. This reduces the rear drive. When rear drive is needed the C solenoid shuts down, so that full Pilot pressure is fed to the spool valve to push it across against spring pressure, to allow full line pressure (red) to flow to the transfer clutch (blue). If the C solenoid fails, full Pilot pressure is fed to the transfer valve, for 50/50 drive. The C Solenoid will post a code if it fails electrically, but most of the faults appear in the transfer valve, that tends to stick. This is due to fact that most of the driving is on highways, at speed, where the valve just sits in the 90/10 position. When the occasion arises when the valve has to move to the full transfer pressure, it sticks there to cause binding, or it does not move at all. So there is no rear wheel drive, and the front wheels just spin. The only difference in the valve assemblies, between the US Transfer system and the Euro AWD system, is the C solenoid. The US type is a normally closed type. The Euro is a normally open type. So the signal fed to them is opposite. Harvey.
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One Arm Bloke. Tell it like it is! 95 Lsi. Bordeaux Pearl, Aust. RHD.149,000Kls Subaru BBS wheels. 97 Liberty GX Auto sedan. 320,000Kls. 04 Liberty 30R Auto Premium. 92.000kls. |
#22
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US models default to closed awd, Euro default to open 2wd. /memorize
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"That which can be asserted without evidence can be dismissed without evidence." '92 Dark Teal SVX LS-L, >146,000m 3 pedals, 5 speeds., restoration underway. 2012 Honda Insight, slow but cute. |
#23
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If it sticks we have binding, and if it does not work at all, we can have front or rear wheel spin. But we always have 40/60 drive. Harvey.
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One Arm Bloke. Tell it like it is! 95 Lsi. Bordeaux Pearl, Aust. RHD.149,000Kls Subaru BBS wheels. 97 Liberty GX Auto sedan. 320,000Kls. 04 Liberty 30R Auto Premium. 92.000kls. |
#24
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So your saying that even though I can get the 4wd to work when I have no power to solenoid C (because it does work when the flow is allowed I have already done the mod), that the TCU is not the prob but the UGH wait
the valve is sticking its not the TCU I can get it to work by replacing the valve. DO you think that if I have the solenoid set to 50/50 for a while the valve might clear up??
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1989 Subaru XT6 130k 1992 Subaru SVX 120k 1993 Ford Probe 30mpg 213k 1989 Subaru XT6 150k All good and running Last edited by spinn360; 03-21-2006 at 08:29 PM. |
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