efseiler Posted February 20, 2011 Share Posted February 20, 2011 Recently I flushed the power steering fluid from the sump in my 96 outback and in addition to basically eliminating the squealing it appears to have greatly ameliorated the so-called 'torque bind' that has been a problem for years in the 4EAT automatic transmission. I guess it may stand to reason since the fluid type is the same in both sumps. I can't think of any other reason why the torque bind just 'went way' suddenly...(enough miles on those snow tires, perhaps) I did bleed air and increase the antifreeze concentration in the radiator, too recently. For a $1.80 hand pump and a quart of ATF it's something worth trying anyway... --Damien Quote Link to comment Share on other sites More sharing options...
idosubaru Posted February 20, 2011 Share Posted February 20, 2011 power steering and automatic transmission are unrelated as they are completely separate systems. should not be any correlation between the two. you may have alleviated some issues in your steering rack by changing the fluid. either way consider yourself lucky for an easy fix! Quote Link to comment Share on other sites More sharing options...
efseiler Posted February 20, 2011 Author Share Posted February 20, 2011 well...this is a case of Mr. Mechanic v. Mr. Engineer. Given that so much of the Subaru's internals are controlled by sensitive electronics it should suprise no one that subtle changes in certain mechanical characterteristics (such as pan fluid viscosity) in one of the drivetrain's components (e.g. steering rack) would alter electronic values (such as bias voltage) and have a cascading effect in the Subaru's entire electronic infrastrucure that could possibly lead to a positive (and possible surprising effect) on other components. The torque bind issue that has been so pervasive in many of the 4EAT transmissions is related to one of the solenoids that is used to regulate piston pressure on the clutch pack used to distribute torque to the rear differential. There is a reason why the fluid type in the steering rack and transmission is the same...both are connected to each other not only mechanically by a belt but also electronically. But...for all I know, a centimeter's difference in tire diameter may have made all the difference... In any case...Mr. Engineer's stupid advice may put you out 7 bucks and leave you feeling used and abused...but trusting Mr. Mechanic may wind up costing you thousands. --Damien Quote Link to comment Share on other sites More sharing options...
Fuzpile Posted February 21, 2011 Share Posted February 21, 2011 (edited) I followed about interactions and even though there is no Dextron ecu I thought u were given consideration. I deflect from your reasoning when you imply that u are mr engineer and a mentor here is mr mechanic. Mechanics are excactly your problem. Mr humble contributor who has Saved many thousand $s is both. Your rack was wacked and before you fluched it, it was giving you power pulses and binding. These cars use a type of CV joint which I think was Rzeppa (you can check). extremely long throw yet sensitive to power pulses- Edited February 21, 2011 by Fuzpile Quote Link to comment Share on other sites More sharing options...
Subaru_dude Posted February 21, 2011 Share Posted February 21, 2011 extremely long throw yet sensitive to power pulses-which to a lib who never even drove a manual steering vehicle, may seem like a torque bind. I'm sorry fuzpile but it appears his car is an automatic. Quote Link to comment Share on other sites More sharing options...
Fuzpile Posted February 21, 2011 Share Posted February 21, 2011 You're twitchin me:lol: Manual steering. Those freakin pumps put out a lot of power even.. i just think it was his jacked rack. Quote Link to comment Share on other sites More sharing options...
efseiler Posted February 21, 2011 Author Share Posted February 21, 2011 Jacked racks...power quacks and tasty Dragon snacks....one puff and the magic's...well...'all that' Quote Link to comment Share on other sites More sharing options...
idosubaru Posted February 21, 2011 Share Posted February 21, 2011 you are correct and fixed your torque bind. all of us here would be extremely wise to consider checking to make sure torque bind isn't steering induced before jumping to the more common, but far more expensive, transmission related torque bind diagnosis. you had binding, but not "typical" torque bind. torque bind isn't an official word or anything so you're right - you had torque bind. your binding though was caused by the power steering rack gears - creating binding between the front two wheels. torque bind as it's usually described, relating to transmissions, includes all 4 wheels front to back and happens in the trans. well...this is a case of Mr. Mechanic v. Mr. Engineer. ha ha, nice try. not that it matters since proficiency in one field doesn't qualify someone for another but since you brought it up, as an aerospace engineer i've had a little training on signal processing and systems before NASA started letting me write code for some of their birds currently in orbit. would you like me to continue replies in hex or binary, i can do both? car systems are not nearly as sensitive as the analogy implies. we swap engines, transmissions, wheel sizes, differentials, drivetrain, air bags, swap steering racks...nearly every and any component - and it never affects torque bind. and here's the key, it's not for any other reason than it just not physically possible. some of us have even driven without working power steering pumps or the pumps disconnected completely ( i've done all of the above).....and there's no torque bind. a car that's that sensitive to fluid between unrelated components would not even be drivable. every weight change, steering change, weather change, component degradation, etc would cause torque bind. it's not even close to possible. Quote Link to comment Share on other sites More sharing options...
efseiler Posted February 21, 2011 Author Share Posted February 21, 2011 well the 'torque bind' symptom in my case was a loud 'thud' I would get after shifting from D to P or N or D...and I'm pretty sure it had something to do with the Duty 'C' solenoid which (I'm told) plays a key role in regulating pressure on the rear clutch pack in the 4EAT. Rumor had it that one of the electrical circuits governing it was 'over-biased' voltage-wise or something.. I guess I'll have to wait until spring when I get the snows off to be sure...but I must attest that frequent AT fluid changes (coupled with Lucas additive) had a very beneficial effect. Perhaps getting the ATF mixture 'just right' may solve it...along with proper oil...gas etc. I guess it's back to 'ounce of prevention worth a pound of cure'. --Damien Quote Link to comment Share on other sites More sharing options...
idosubaru Posted February 21, 2011 Share Posted February 21, 2011 okay this sheds some new light on things, we might be able to narrow this down. sorry for being verbose but some things aren't lining up, just missed communication so I'm going to define some things and see what your experience might say about them. sharp thuds from neutral or park into drive is relatively well known and typically referred to as "Delayed Engagement", but is usually strangely limited to 1999-ish auto trans. Auto Trans X is the recommended fluid for mitigating that issue in that year. There's an entire thread about that. If that's your issue I'd change the fluid again and go with the Auto Trans X. Torque bind in the trans doens't usually reveal itself when going into park/drive, it's usually most noticeable when going around sharp turns in parking lots...car bucks, hops, with a braking sensation. if you didn't have those, then it's unlikely you had torque bind. those of us, like myself, that have spliced into the wiring to manually control the Duty C ourselves are very familiar with what it feels like. some of us prefer having control over it in some situations. I must attest that frequent AT fluid changes (coupled with Lucas additive) had a very beneficial effect.this post suggests the ATF was changed in the transmission. the original post implies you changed the power steering fluid (in the power steering pump presumably). which did you do, or was it both? except when the Duty C solenoid is failing and after checking for matching tires, changing the ATF is always the first step to fixing torque bind in the trans. that's common knowledge and what is recommended throughout the subaru community. Quote Link to comment Share on other sites More sharing options...
wally Posted February 21, 2011 Share Posted February 21, 2011 changing the ATF is always the first step to fixing torque bind in the trans. that's common knowledge and what is recommended throughout the subaru community. only for an auto. t/b happens in the manual trans subies too. whole 'nother animal. Quote Link to comment Share on other sites More sharing options...
efseiler Posted February 22, 2011 Author Share Posted February 22, 2011 well it's not torque bind then. When I first got the vehicle it had about 143,000 miles on it. One day the transmission light started flashing on startup. I checked the fluid and it was fairly dirty and low so acting on a tip I topped it off with Lucas stuff. After a couple hundred miles of driving the flashing light went away altogether. Then, when I had the chance I basically flushed the tranny (by drain fill X 4) and used name brand ATF that presumably was quality stuff. Since then, I've been refreshing the ATF every 7-10,000 miles. The original 2.5L engine blew a gasket completely around 175,000 miles so I had a 2.2 put in. It has nearly 225,000 miles on it now. The 'thud' problem has been with the tranny since maybe around mile 200,000... Now recently my steering rack started squealing so I flushed the fluid and now the squealing has gone away. But not long after that the 'thud' problem basically went away also. My 'mechanical intuition' told me that perhaps there was a connection between those two components that affected each other in non-obvious ways (I'm thinking similar vibrational emissions as a result of the fact that both use the same fluid in their respective operations). The fact that the rack ATF was so old and dirty (and perhaps of very different composition altogether than the trans. ATF) perhaps caused a kind of mismatch that lead to some sort of unforeseen mechanical load resulting in the transmission problem. --Damien Quote Link to comment Share on other sites More sharing options...
efseiler Posted February 22, 2011 Author Share Posted February 22, 2011 on second thought...there is some true binding issues with this trans. But I don't think it's very severe....it does lurch and 'pulse' somewhat on a sharp turn from a full stop. Is that such a symptom? --Damien Quote Link to comment Share on other sites More sharing options...
idosubaru Posted February 22, 2011 Share Posted February 22, 2011 Torque bind is always noticed going around turns. It has to do with the AWD system and geometry of going around a turn. When you turn your steering wheel the front and rear wheels follow different tracks and therefore are rolling at different speeds. This causes binding when the 4WD mechanism won't allow any "slip" for them to roll at different speeds for the different arcs they are traversing. Easiest way to tell is on dry pavement in a parking lot. With the steering wheel turned as far as it can go you'll feel a braking sensation, like the car slowing down faster than normal. That is classic torque bind. Wheels will slip as well, usually the rear it seems like. Frequent changing of the transmission fluid can alleviate torque bind. If the torque bind is related to the Duty C then no fluid changes or additives can fix it, it's just a failing solenoid. There's two standard causes to AT torque bind. Your best bet is to use regular ATF like you said you did. There's no need for high end stuff or additives, none of that adds any value here. I would pass on the lucas recommendation from others, it's not well thought of in this scenario. In general, additives can sometimes help, or seem to help, in the short term but aren't good for the trans long term. So they're generally considered a band-aid except in a few instances, or a car that's not worth much effort. A "thud" as you describe it, could be a whole litany of things. There's any number of bushings that can cause noises like that - steering rack, cross member, rear diff, exhaust, etc. And nearly any bushing in the car will cause noise under different loads, changes, etc. Quote Link to comment Share on other sites More sharing options...
efseiler Posted February 22, 2011 Author Share Posted February 22, 2011 well alright...you did give me a couple of pieces of useful knowledge...thanks! Cheers! --Damien Quote Link to comment Share on other sites More sharing options...
cj7135 Posted February 24, 2011 Share Posted February 24, 2011 Does anybody know if Duty C solenoid and clutch pack can be used out of a 98 Forester AT for a 97 OBW AT? Quote Link to comment Share on other sites More sharing options...
idosubaru Posted February 24, 2011 Share Posted February 24, 2011 Does anybody know if Duty C solenoid and clutch pack can be used out of a 98 Forester AT for a 97 OBW AT?should be the same. Quote Link to comment Share on other sites More sharing options...
WoodsWagon Posted February 24, 2011 Share Posted February 24, 2011 Now recently my steering rack started squealing so I flushed the fluid and now the squealing has gone away. But not long after that the 'thud' problem basically went away also. My 'mechanical intuition' told me that perhaps there was a connection between those two components that affected each other in non-obvious ways (I'm thinking similar vibrational emissions as a result of the fact that both use the same fluid in their respective operations). The fact that the rack ATF was so old and dirty (and perhaps of very different composition altogether than the trans. ATF) perhaps caused a kind of mismatch that lead to some sort of unforeseen mechanical load resulting in the transmission problem. --Damien No. I'm a lowly mechanic and I agree with the aerospace engineer a few posts up. You can't have a "holistic" healing approach to a car, the yin and yang of different fluids in completely unrelated components will not create sympathetic vibrations. Sorry, but no. The power steering system consists of the rack, a pair of hoses, the pump, and a belt to the crank. There is no electrical interaction with any other part, it's a purely hydraulic system and is isolated from any other system on the car. Oh, and racks don't squeal, pumps or belts do. Pumps usually whine, and belts usually squeal, but no matter. Changing power steering fluid won't get rid of AWD binding problems on tight turns. Quote Link to comment Share on other sites More sharing options...
efseiler Posted February 25, 2011 Author Share Posted February 25, 2011 *shaking head* Ye have little faith... Quote Link to comment Share on other sites More sharing options...
987687 Posted February 25, 2011 Share Posted February 25, 2011 It's good that a flush fixed your power steering issue... Be glad it wasn't a transmission issue. Quote Link to comment Share on other sites More sharing options...
mdjdc Posted February 25, 2011 Share Posted February 25, 2011 Don't be surprised if you find that the rear drive drum has sheared off the shaft is is only free spinning now. I bought a car that had no apparent torque bind issues, but the duty c was bad. When I got into it I found that the freedom was a result of the drum shearing off the back of the drive gear on the shaft. I had to replace that and the solenoid to get back to AWD. The PO had just continued to drive the car in bind until the selds on the drum let go. Not the best way to go. Quote Link to comment Share on other sites More sharing options...
WoodsWagon Posted February 25, 2011 Share Posted February 25, 2011 *shaking head* Ye have little faith... Faith based automotive repair has never worked for me. It's a machine with no spirit/soul so only the laws of physics and not spirituality apply to it. I have a HHO generator I can sell you though... double your gas mileage using power from your alternator to make fuel from water. Quote Link to comment Share on other sites More sharing options...
987687 Posted February 25, 2011 Share Posted February 25, 2011 I had faith that my loyal little subaru would heal it's front axle on it's own, but it broke Quote Link to comment Share on other sites More sharing options...
Narrowpath Posted February 26, 2011 Share Posted February 26, 2011 Hey guys...I'm new on here and just bought a 93 Subaru Legacy AWD Wagon. Its an auto and came with a few problems. I believe it has torque bind issues, but not sure. I get some what feels like a cog on the gear skipping when I accelerate at low speed. Once up to speed 30+ I cant get it to do it. If I ease away from a stop sign it usually does not do it. I have installed FWD fuse which eliminated it. I raised the car off the ground and put her into gear. With it in all wheel drive and the wife giving it some gas and then letting off, I observed a major thump/jerk in the car that is coming from the tranny, causeing all the rear end to clank/bang. No issues in FWD.... I was assuming torque bind would be eliminated with the wheels off the ground??? Is it a transfer clutch.....but why with the tires off the ground? Any help would be great...not even sure if this is the best place to post. Quote Link to comment Share on other sites More sharing options...
Narrowpath Posted February 26, 2011 Share Posted February 26, 2011 (edited) double posted here my above message.....cant find out how to delete it......off to a good start Edited February 26, 2011 by Narrowpath Double posted Quote Link to comment Share on other sites More sharing options...
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