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I've gone back and read all I can about Torque Bind. I have a 97 Legacy that seemed perfectly fine until I got the transmission fluid changed at my local garage. Ever since then I've had a torque binding problem on turning. It's my daughter's car so I did not know about it until about two weeks after the problem started. While the car was at the garage the mechanic also changed the cv boot which was ripped. My questions:

A) Could the transmission fluid change cause the problem?

B) Could changing the CV boot introduce a problem?

C) What are the best inexpensive fixes. Without seeing it the Subaru dealer suggested the clutch packs shoudl be replaced. Right now there are no warning lights etc, Just some torque bind on turning.

D) How much damage is caused by ignoring it?

 

Thanks

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A- doubt it unless they used the wrong type fluid.

B- no

C- Check the tires and make sure they match, and that they are all properly inflated. Put the FWD fuse in the holder and see if it d=goes away. Its usually an 800.00 fix

D- What exaclty did the shop do to the car? Never ever take a car to a transmission shop for any work short of a slipping transmission. Torquebind can make the car handle poorly in bad weather, to the point of being dangerous in the right conditions. The car can get worse mechanically, and put a lot of stress on the differentials, cv joints and u joints.

 

How many miles are on the car?

 

nipper

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in addition to nippers comments, i will add that ignoring it is a very, very bad idea. you will cause premature failure in various drive train components and wear your tires faster, i'll guess axles will be the first to start going out.

 

those things shouldn't "cause" it. if you don't typically drive it my guess is that it had problems before this work, you just didn't know. but...if you're still suspicious i'd check the fluid level and color to make sure.

 

if the $800 clutch pack replacement isnt' suitable, just run it in FWD with the fuse in. i've done it, i'm doing it, and know others are now too, it'll be fine. of course this is only suitable if the FWD fuse even works. if you put it in and still have TB then it won't work.

 

let us know how the FWD fuse goes.

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there are several causes of torque bind in multiple combinations. if it's not tire related, most common is the failure of the duty-c solenoid. (usually you get a flashing AT TEMP light at start up) this is a 75$ part from an online dealer and labor is about 300$. second is the transfer clutch plates. these are not terribly expensive either and the labor is about the same. the risk is doing one and not the other only to find you need to replace both. therefore the good fix is both for 800$.

 

some of the earlier AWD trans could suffer from dirty fluid , plates and/or duty-c. 97 is about when they made a correction, but i think 98 to be sure. usually this was helped by a fluid change. but not always. some people have had success with an additive.

 

you need to figure out what's causing the problem first. put in the FWD fuse and see what happens.

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some of the earlier AWD trans could suffer from dirty fluid , plates and/or duty-c. 97 is about when they made a correction, but i think 98 to be sure. .

 

1997 1/2. Thats why when mine went i let the dealer do it, as they replaced all the parts with the re-engineered parts to correct the leaking seals.

 

nipper

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Thanks guys. Farely low milage at about 140,000 kilometres on the car. I did not take it to a transmission shop, just my local garage where they do most of the work on the car. They suggested a tranny fluid change and since the car was in I figured it wouldn't hurt. I'll try the fwd fuse and see how that works. I've read to change the fluid two or three times in a row to flush out all the old fluid and crap so I think I'll get that done first and maybe try an additive.

If that doesn't work it's off to the dealer for the real work...

Thanks guys

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ok I inserted the FWD fuse and the problem has gone away. The FWD light is on on the dash and the binding seems to be gone...

Just a note: i took the car to work this evening and there was a little snow storm while I was at work. Holy smokes what a difference. I have been driving Subaru AWD for more than 10 years and I basically have not driven any other car. For the first time in ten years I was very tense coming home. The car's wheels were spinning like there was no tomorrow and the rear end just did not have that secure feeling I get with AWD. When you have it you really don't realize how bad it is for everyone else...

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Having studied and corrected my torque bind issue on my 96 Outback, I learned a lot about the system. See my post

 

http://www.ultimatesubaru.org/forum/showthread.php?t=78467

 

I must admit that I didn't repair mine as described in splended help provided in that post, but found a low miles tranny for less than I believed possible, disassembled the tail shaft housing to inspect the clutch plates, and for good measure, replaced the duty solenoid C while I had the new tranny on the table. So far ~7,000 miles and no problems. I will repair my original and sell it in the near future as the transmission and transaxle were fine making it worth the fix.

 

It is my understanding that if inserting the fuse to create the Front Wheel Only mode corrects the problem then Duty Solenoid C may be good and that the clutch plates are either hanging up or not being permitted to disengage. The fuse really is only a jumper to permit a chassis ground to energize the duty solenoid and remove output to the clutch pack.

 

Hence, if the solenoid is disabled and the problem goes away that means that the solenoid is capable of energizing and de-energizing appropriately. Thus when not disabled by the fuze, the solenoid is enabling torque to the rear drive shaft.

 

That said, the duty solenoid mounts to a hydraulic manifold in the tailshaft entension housing which, through very small drilled ports. When enabled it ports hydraulic fluid (read pressure) to enable the clutch pack to engage and enable rear drive shaft torque. If that manifold became plugged by debris it would seem that the system could malfunction and torque bind could occur even if the solenoid itself were functional.

 

Given that you had no symptoms prior to trans fluid service it would seem that this scenario most fits your description of events. I can't discount what Click and Clack the Tappet Brothers, the Public Radio hosts of the radio talk show Car Talk, refer to as "vital crud". This refers to material that can be dislodged in a pressure flush trans fluid change and migrate to be a problem in another place. Perhaps that is your problem. One would have to, at minimum, remove the tailshaft housing to access the solenoid and the manifold it mounts to. If I went that far I wouldn't even try to clean it. I'd just put in a new one.

 

One can not however totally discount the possibility of the clutch plates hanging up and not disengaging even though the duty solenoid itself is working correctly and hydraulic pressure is removed. This would seem unlikely given the failure mode you describe. Nevertheless, if so, that problem may continue to worsen despite the fuse being in place for if the clutch plates are sufficiently bound together, the torque bind will likely worsen with or without the hydraulic pressure to them.

 

Steve

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Evereyeon seems to forget that there is one more valvein the suystem, its not 100% the duty c solenoid. The pre 1997 1/2 have a poor seal seats which subaru freely admits.

 

In computerized trannies, espescially subaru, its ben proven over and over flushing does not kill them. Thats back in the bad old days with older materials, and many more moving parts. Thats not an issue anymore.

 

 

and i love Click n clack, its some of the other know it alls who sound like hour long commercials i can do without.

 

nipper

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And here is your cheap fix. Go to a parking lot and perform several tight figure eights. It worked for me to lossen the clutch paks up. The second cheap fix is adding in the limited slip deffeential oil from Dodge driving for a few miles and chaning the fluid. I did not have to get to this stage but people on this forum have suggested it.

 

As stated make sure your tires are all the same and at the correct air pressure.

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Thanks for all your responses. I have taken a selection of them and emailed them to the garage. Will let you know what happened. The car will go to the garage tomorrow to see if we can solve the problem with some quick and dirty solutions. If not, I plan to let my daughter drive it in FWD for a while until I can afford to get the repair done properly at the Subaru dealership...

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If there is snow on the road, there is not any problem driving it in AWD. Remove the fuse if it's snowing. Torque bind is only bad for the car on dry and mildly wet pavement.

 

 

The clutch pack are obviously not siezed or dragging. If they were, the FWD fuse would do nothing. Clutch pack disengagement is passive. The electronics and hydraulics cannot force it to disengage. They can apply force to engage it, and remove those forces, but it must freely, with nothing more than the force of a few small springs,disengage itself when hydraulic pressure is removed(FWD FUSE)

 

It is doing just that when the fuse is inserted so it cannot be a siezed clutchpack, or defective C solenoid.

 

What it can be is a faulty TCU, or faulty sensors

 

I would suspect the speed sensors or throttle position senor.

 

Have a dealership check the TCU fault codes

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Lets review.

 

Installing the fuse sends a signal to the ECU to hold the Duty C solenoid wide open. This dumps all the hydraulic pressure to the clutch pack, and bypasses the internal pressure valve.

 

If The Internal pressure valve (which is a spool valve) has an erosion issue (causing leaks), this action will disable the AWD.

 

If the clutch pack has internal seal leakes, again, the DUTY being held wide open will dump all the pressure and not allow the clutchpack to engage.

 

Everyone seems to forget that there is far more to the AWD system then just a solenoid and a valve.

 

http://legacycentral.org/library/torquebind.htm

 

 

 

Just food for thought.

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As always, an interesting discussion.

 

No one has asked the Gent if he get's a transmission failure indication in the form of a blinking trans temp light after start-up. Unless I'm mistaken this would lead one to an electronic/electrical component as opposed to mechanical fault such as clutch plates that might be hung-up.

 

I certainly don't know the answer but I do know that in it's final days of failure my trans clutches would not bind with the fuse inserted until after driving a few highway miles. After driving the clutches locked as tight as the front end on my old chevy 4x4 truck. I absolutely couldn't even pull out of the traffic lane into a parking place at walmart without a problem. Earlier on in the failure mode having the fuse in seemed to work to disengage the clutches; or so it seemed.

 

The significant point is that things had to warm up before the failure manifested itself as torque bind. Go figure.

 

I think (don't know for sure) that the clutch plates were dragging but not engaged as when hydraulic pressure is pushing them together. I do know that at least before I replaced it all, the duty solenoid did show up as a fault when I read the trans control module codes.

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As stated make sure your tires are all the same and at the correct air pressure.

 

Measure all the tires yourself while it is on the lift.

They're not supposed to be more than a 2-3/32 inch, I think? different in diameter.

Seems like you have the ability to engage and disengage the clutch pack still.

I'm holding out for flushes.

Curious to see how it turns out.

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Ok latest update. I took the car back to the garage, sent them a number of your comments. They changed the AT fluid a second time and put some additive in and my daughter reports that the torque binding is gone. I have not had a chance to test drive it yet but I will tomorrow and report back. Might have gotten lucky with this one....

thanks... keeping my fingers crossed.:banana:

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I just had to go the expensive route and paid the $800 to fix it. To me it is worth it as this car was free to me and was starting to cost me some in tires and breaks and whatnot. I just have to get some breaks and rotors and my car will be in much better shape!!!

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Ok I did get a chance to drive the car a little this morning. Initially I thought it was perfect. No torque bind in simple cornering. Even tighter corners at normal speed felt perfect. On my return trip I noticed a slight (very slight) bind on a slow sharp turn. So I am hoping it will continue to get better and completely go away. But I realize that the opposite could occur and that the problem will get worse. Time will tell here but it is, for the time being about 99 per cent perfect.

 

On an earlier post someone asked if I was getting any warning lights on the dash. The answer to that is no. No warning lights at all....

 

I think there is hope that this will go away only because the car had no symptoms until the AT fluid was replaced. If it had earlier symptoms and the tranny fluid change made it worse I would think an immediate clutch pack would be in order but because this seemed to be caused by an AT fluid change, I am more confident that it can more or less correct itself...

Car has 147,000 Kilometres...

Thanks I'll keep you informed over the next few weeks.

Fingers crossed

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Ok I did get a chance to drive the car a little this morning. Initially I thought it was perfect. No torque bind in simple cornering. Even tighter corners at normal speed felt perfect. On my return trip I noticed a slight (very slight) bind on a slow sharp turn.

 

Ya know, it is an AWD car. Some amount of torque transfer should happen all the time. Even in turns. AWD doen't help much if it only work going straight.

 

This will manifest a small binding. Most noticable at very slow speeds. Since *turn* and *slip* are detected by the TCU using the VSS(speed sensors),At very low speeds, it is hard for the TCU to *decide* that the car is in a turn, and to then lower the transfer pressure.

 

Don't get me wrong, problematic, major, torque bind can, and does, happen. I am merely saying you're case here does not sound that bad. I wouldn't worry unless something get worse

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Ok I did get a chance to drive the car a little this morning. Initially I thought it was perfect. No torque bind in simple cornering. Even tighter corners at normal speed felt perfect. On my return trip I noticed a slight (very slight) bind on a slow sharp turn. So I am hoping it will continue to get better and completely go away. But I realize that the opposite could occur and that the problem will get worse. Time will tell here but it is, for the time being about 99 per cent perfect.

 

On an earlier post someone asked if I was getting any warning lights on the dash. The answer to that is no. No warning lights at all....

 

I think there is hope that this will go away only because the car had no symptoms until the AT fluid was replaced. If it had earlier symptoms and the tranny fluid change made it worse I would think an immediate clutch pack would be in order but because this seemed to be caused by an AT fluid change, I am more confident that it can more or less correct itself...

Car has 147,000 Kilometres...

Thanks I'll keep you informed over the next few weeks.

Fingers crossed

 

What type of flush did they do? Total or just partial drain.

I have heard it that you have to do three or more partial drains just to change out the old fluid totally.

 

If you really think it's torque bind flush again! Try to see if you can get by without the additive this time. You can always put it in later.

 

Not sure if driving it for a few weeks like this first wouldn't help?

 

Glad for your partial success.:lol:

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