AT Oil light flashing; some torque bind + more

[eseiler]

Hello Subaru fans,

I recently changed the AT fluid in my 96 OB Wagon...soon thereafter the AT Oil light would flash repeatedly at startup. Then, I noticed some torque bind rounding tight corners at low speeds. Most disturbing, however, was when parking and shifting into Neutral and Park I would hear a big clunking sound which was apparently coming from the rear end.

 

My investigation has lead me to believe an electronic failure with the transmission (I'm guessing a Duty Solenoid (C?) ) I did notice when changing the rear diff fluid around 30k miles ago that there were some solid pieces of metal stuck to the plug magnet. I'm guessing the rear diff days are numbered but the AT light definitely has me concerned.

 

Upon the recommendations of some local Subaru mechanics I did put in about 10oz of LubeGuard in the tranny.

 

Your input would be appreciated!

 

Thanks...

 

-Damien

[lmdew]

If it started right after the fluid change, I'd say you broke a wire if you were in the pan to change the filter.

 

It could be that some dirt has broken loose from the new fluid and clogged the C-Duty flow. Have you tried the FWD Fuse? That will tell you if the wire is broken.

[MountainBiker]

I did notice when changing the rear diff fluid around 30k miles ago that there were some solid pieces of metal stuck to the plug magnet.

That is what you should be worried about! Got any pics?

[eseiler]

That is what you should be worried about! Got any pics?

 

Pics of what? Tell me and I'll happily take them.

 

What the procedure with the fuse thing?

 

Muchos gracias!

 

-Damien

[eseiler]

Pics of what? Tell me and I'll happily take them.

 

What the procedure with the fuse thing?

 

Muchos gracias!

 

-Damien

 

What was stuck to the magnet was mostly metal 'dust' but also a couple of fragments of metal...both of which looked like parts of a metal ring.

 

--Damien

[nipper]

You most likely have a duty C failure of some kind. The duty c can be stuck, burned out, shorted, name your poisin.

Now with the age on the car, im going to assume it has some miles on it. Make sure your sitting down when you hear the price of the repair. The TB will also make the rear end wear out faster.

Now the clunk. The clunk is fairly easy. What you are hearing is your driveshaft winding up under TB. WHen you put the car in park or neutral you are suddenly unloading the driveline, hence the clunk. Bad news is that that is your universal joints complaining. Get the car to a shop asap, before you do alot more damage.

Try the FWD fuse, but i get the feeling its not going to work. If it does all the better, but i needs to be fixed.

The chunk of metal. The rear will give LOTS of warning before it slef destrusts if it is a ring gear. IF its a planetary gear the car will make a weird noise out of the rear at 2Xs the wheel speed. IN a awd car you may not even notice that, but keep an eye on it. Rear diffs are relativly tough.

 

nipper

[idosubaru]

i wouldn't worry too much about the rear diff right now. that's not likely to cause you any problems any time soon like nipper said. they'll make tons of noise and still won't fail.

 

same with clunk, it's related like nip said. focus on the trans for now.

[eseiler]

i wouldn't worry too much about the rear diff right now. that's not likely to cause you any problems any time soon like nipper said. they'll make tons of noise and still won't fail.

 

same with clunk, it's related like nip said. focus on the trans for now.

 

Well I put the fuse in and no more flashing AT light...car runs quite smoothly now.

 

--Damien

[johnceggleston]

if you just had TB, i would say flush it again, but like they said, with the at temp light, it's the duty c, flushing is not going to change that.

 

who did the flush? did they pull the a/t pan? is it possible they damaged something inside by accident? i'm always suspecious when something fails right after service.

 

i wouldn't worry too much about the rear diff right now. that's not likely to cause you any problems any time soon like nipper said. they'll make tons of noise and still won't fail.

 

same with clunk, it's related like nip said. focus on the trans for now.

[eseiler]

if you just had TB, i would say flush it again, but like they said, with the at temp light, it's the duty c, flushing is not going to change that.

 

who did the flush? did they pull the a/t pan? is it possible they damaged something inside by accident? i'm always suspecious when something fails right after service.

 

I did it myself...all I did was drain 4qts of ATF and put in 4qts more. This was after about 15k miles after what was basically a flush (80% of ATF replaced).

 

--Damien

[nipper]

You should have done it twice to get all the junk tou (actually three times is what we recomend here). YOu will still have to get it looked at, as the solenoid has some sort of issues. There are two parts to the system, the solenoid and an internal spool valve. I would do a full flush and see if there is just some gunk making the solenoid stick, but it sounds to me like the solenoid is weak.

 

nipper

[bejizimit]

Howdy folks!

 

I am having that TB on a 1990 Legacy SW AWD, 210,000.

 

I ran the TCU shift code read, and while I didn't have any "current" codes, the previous codes indicate the Duty C solenoid.

 

I got testing data from AllDataOnline at the library, but unfortunately, there are no pictures of compoment locations.

 

Does anyone have a link to pics of where the duty C is located, where the wiring connector is, etc.

 

If the solenoid is bad, what's involved with changing it? I've heard that the end housing needs to be removed, but this can be done without removing the tranny.

 

Thanks for any info!

[nipper]

Howdy folks!

 

I am having that TB on a 1990 Legacy SW AWD, 210,000.

 

I ran the TCU shift code read, and while I didn't have any "current" codes, the previous codes indicate the Duty C solenoid.

 

I got testing data from AllDataOnline at the library, but unfortunately, there are no pictures of compoment locations.

 

Does anyone have a link to pics of where the duty C is located, where the wiring connector is, etc.

 

If the solenoid is bad, what's involved with changing it? I've heard that the end housing needs to be removed, but this can be done without removing the tranny.

 

Thanks for any info!

 

i dont ever recalling anyone just doing the C on a car with that mileage. If you havent been driving it i guess it can be done, just dont be surprised if the clutchs are tired also.

People here have replaced thier C before, ild say do a search, but there is most likely too may posts here to find it.

 

I can send you a pdf on a newer tranny (most likely the same ) on how its done. It just requires removla of the pan and valve body.

 

nipper

[89hatch]

Nipper, I'll be trying the duty C only repair myself and would sure love to take a look at that pdf as well. Although I thought it required removing the tail end of the tranny since that's where the duty C is located. Either way, could you please send it to cbarrls6(at)msn(dot)com? Thanks

 

i dont ever recalling anyone just doing the C on a car with that mileage. If you havent been driving it i guess it can be done, just dont be surprised if the clutchs are tired also.

People here have replaced thier C before, ild say do a search, but there is most likely too may posts here to find it.

 

I can send you a pdf on a newer tranny (most likely the same ) on how its done. It just requires removla of the pan and valve body.

 

nipper

[eseiler]

How do I clear the memory of the TCU on those Phase I 4EAT transmissions?

 

 

--D

[89hatch]

Pull fuse #14 in the fuse block under the dash on the driver side for at least 1 minute.

 

How do I clear the memory of the TCU on those Phase I 4EAT transmissions?

 

 

--D

[johnceggleston]

Howdy folks!

 

I am having that TB on a 1990 Legacy SW AWD, 210,000.

 

I ran the TCU shift code read, and while I didn't have any "current" codes, the previous codes indicate the Duty C solenoid.

 

I got testing data from AllDataOnline at the library, but unfortunately, there are no pictures of compoment locations.

 

Does anyone have a link to pics of where the duty C is located, where the wiring connector is, etc.

 

If the solenoid is bad, what's involved with changing it? I've heard that the end housing needs to be removed, but this can be done without removing the tranny.

 

Thanks for any info!

 

it is inside the extention housing.

look here:

 

http://www.ultimatesubaru.org/forum/showthread.php?t=50543

 

and here:

http://smg.photobucket.com/albums/v204/All_talk/Subaru/4EAT/?

[89hatch]

Wow, great info. I searched high and low for topics, but somehow missed this one. Thanks

 

it is inside the extention housing.

look here:

 

http://www.ultimatesubaru.org/forum/showthread.php?t=50543

 

and here:

http://smg.photobucket.com/albums/v204/All_talk/Subaru/4EAT/?

[Wayne Boncyk]

There's more on this forum, too. Search on posts by me from about this time last year, and earlier. You'll find that I experienced the same symptoms, and did exactly the same thing you have done thus far (i.e. the FWD fuse). I ran for a very long time before getting around to disassembling the rear extension housing on my AT, but the bottom line is that you can do the work yourself, replacing the Duty Cycle C solenoid, with the manifold switch under it, takes about 5 mins once you have the extension housing removed. If you find either sticky clutch plates (where two or more don't move freely with respect to each other) or if you find scoring inside the extension housing (since until 1997 they didn't use a bearing on the extension housing and the output shaft could wear the housing enough so that the clutch plates would start rubbing on the inside of the housing itself), then you'll have to replace those parts, too. Nevertheless, if you're at all mechanically adept you can do this all yourself for probably around $100-$250 in parts (some used) vs. the $800-$1100 you'd have to shell out if you went to a dealer to have the work done.

[89hatch]

Yep, he's right. Search for his thread from 2004 with his 96 Outback. There are also a few FSM scans in that thread. I printed it out and used it to diagnose my blinking Trans Temp light using nothing but this thread just this past weekend. I've done all the work myself to keep prices down. One question, what is the manifold switch you're referring to? It looks like there's 2 gaskets and a plate between the duty C and the trans housing. Where's the manifold switch and what does it do? Thanks

 

There's more on this forum, too. Search on posts by me from about this time last year, and earlier. You'll find that I experienced the same symptoms, and did exactly the same thing you have done thus far (i.e. the FWD fuse). I ran for a very long time before getting around to disassembling the rear extension housing on my AT, but the bottom line is that you can do the work yourself, replacing the Duty Cycle C solenoid, with the manifold switch under it, takes about 5 mins once you have the extension housing removed. If you find either sticky clutch plates (where two or more don't move freely with respect to each other) or if you find scoring inside the extension housing (since until 1997 they didn't use a bearing on the extension housing and the output shaft could wear the housing enough so that the clutch plates would start rubbing on the inside of the housing itself), then you'll have to replace those parts, too. Nevertheless, if you're at all mechanically adept you can do this all yourself for probably around $100-$250 in parts (some used) vs. the $800-$1100 you'd have to shell out if you went to a dealer to have the work done.

[89hatch]

Here's a link to a thread about my issues with the duty C I'm currently going thorugh

http://www.ultimatesubaru.org/forum/showthread.php?t=63094

 

At the bottom of page three is the link to Wayne's thread from 2004.

[Wayne Boncyk]

Actually, I was a little unclear. The Duty Solenoid and that manifold plate together comprise a switch. It changes the relative pressure of AT fluid on one end of the clutch plate assembly, which causes the plates to couple power to the rear driveshaft when they're engaged by that switch. Note to those of you who are trying this at home -- make sure that you either change out that manifold plate (and its gaskets) or that you are sure that there are no obstructions in the channels cut into the plate, or all your hard work getting to and swapping out the Duty Solenoid will be for nothing.

[89hatch]

Great post...I did not know that:D Maybe before ordering any parts, I should remove the tail end of the trans and take a look at the plate. Maybe I'll get lucky and there are obstructions in it. Is there anyway to test with a volt meter to see what's going on without taking the tail shaft off? Like voltage at the FWD fuse holder or anywhere else? If so, what should the voltage be and when? I don't have torque bind, but the opposite: No light when I put a fuse in the FWD and it seems like it's always in FWD(tried it in the rain). Thanks for the insight.

 

Actually, I was a little unclear. The Duty Solenoid and that manifold plate together comprise a switch. It changes the relative pressure of AT fluid on one end of the clutch plate assembly, which causes the plates to couple power to the rear driveshaft when they're engaged by that switch. Note to those of you who are trying this at home -- make sure that you either change out that manifold plate (and its gaskets) or that you are sure that there are no obstructions in the channels cut into the plate, or all your hard work getting to and swapping out the Duty Solenoid will be for nothing.

[nipper]

Word of advice, use the search engine (topic and the posters nic), otherwise you will get flooded with hits, especially on TB and HG.

 

 

nipper

[bejizimit]

Thanks for the link to the great pics!

 

Just a question on the location of the wiring connector for the duty c solenoid on that '90 legacy.

 

Which side of the tranny or end housing is it located. According to the diagnostics, I should measure the resistance of the solenoid, the ground line, and the harness between the tcu and connector.

 

Where's the connector?

 

Also, where do you place the fuse on the FWD switch? Is that located on the firewall?

 

My problem with the torque bind is intermittent. I can drive for 100's of miles with no problem. Then,all of a sudden when I slow down and turn, I get the TB! After I turn the car off, the whole car moves, like it's "relaxing". The next time I start, the power light blinks the 8 secs, then I drive for 100's of more miles.

 

With the intermittent problem, I'm thinking maybe the connector is dirty or loose.

 

I had the transmission rebuiltback in Apr 2005. This was done after the problem was id'd as "binding or bucking on turns" - transfer clutch worn out. My rear tires were severly cupped, and it felt like they were being dragged during turns. I took the car to a trans shop, and they decided that the trans needed rebuilding, with the comment, "what were you doing to this? this transmission is a mess!"

 

The torque bind started showing up last May. I've about 210K on the car.