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Guest Message by DevFuse

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transmission control module

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8 replies to this topic

#1 Guest_juancolorado_*

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Posted 18 June 2003 - 12:49 PM

2000 Outback wagon

I am about to replace my transmission control module for the 2nd time. This is the unit that controls the shifting of the automatic transmission. Has anyone else had problems with this unit?

I also posted about a noise, but did not get any responses. So........I will ask here. Front end noise, sounds like a heavy suspension noise, but the mechanics say it is the sound of the strut action. I realize no one can diagnoise a noise without hearing it, but the end result is they say it's the action of the strut that makes the noise. So with that said, is this a common noise coming from all struts? Does everyone experience strut action noise? I never heard of this and I still believe it is something loose, but I can't find it. Never had it before in any vehicle. ????

Thanks for replies,


#2 Guest_Legacy777_*

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Posted 18 June 2003 - 04:50 PM

why are you replacing the transmission control unit? What is wrong?

where in colorado are you located. Sounds like you need a new mechanic.

#3 Guest_Commuter_*

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Posted 18 June 2003 - 05:04 PM

I can't comment about the ECU. I have a 97 OB and I recently had to replace a tiny (expensive) pressure sensor that mounts on the passenger strut tower. It was messing up the shifts a little bit. (They were a little slow, or delayed.) You didn't say what the symptons are. And I don't know if the newer OB's are still confitured this way. I'm presuming you have the 2.5L engine since you didn't say.

Strut noise...or better (and more generally) put, front end noise. This was a very common topic when I first came on this board over 3 years ago. The mid to late 90's Legacy's / OB's have this issue. If one front wheel goes over a slight dip or bump (ie near a storm drain) or if you turn into a driveway and cross thru the rain gutter to an incline... one would often get a "clunk". There were TSB's on it if I'm not mistaken. One school of thought related it to some power steering issue. (Some sort of kick back I think... they were changing hoses? Minimal success rate IIRC.) Another school of thought placed it as a "suspension" issue whereby nothing is really wrong, it's just that 'customer expectations' have not been met with regard to noise levels. (Sort of like the explanation on piston slap.)


I don't know if this is still an issue with the newer generation of Legacy / OB cars. I certainly haven't seen much discussion about it. I bought my car used at 2 yo and came to notice the clunk over time. The dealer agreed and changed out one strut under warranty. After that, it was better, and seemed to be localized on the other side of the car. I tried to get them to change the other strut, but they "couldn't reproduce" the noise and it was left as is. 4.5 years later, I still have the original strut in there. My noise is not as bad as what some people had. Also, I have my car sprayed yearly with Rust Check. By the second application, the noise seemed to have all but disappeared. And no, it's not that I just got use to it. I still hear it occasionally under the right circumstances.

So... I personally think that it might have something to do with the mounting of the strut (and/or suspension components) as opposed to the strut internals. What can you do about it? No clue really. You might try a strut bar, but I don't know if that will help. You could try one of the rust inhibitive sprays, see what happens. Other than that, just live with it. If you can't ... time for a trade I guess.

I hope this helps. Again, this experience is with the late 90's platform, not the current platform.


#4 Guest_hocrest_*

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Posted 18 June 2003 - 08:28 PM

On the strut noise...
I noticed it on mine when I got it 4 1/2 and 120,000 miles ago. Sort of a squoosh when hitting a bump at "Parking Lot Speed"

Since it has lasted this long I figure it's normal???

#5 Guest_juancolorado_*

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Posted 19 June 2003 - 06:34 AM

The TCM is the unit that controls the shifting of the transmission (in my case the downshifting). My outback would "slam" into a downshift when it recognized that I was slowing down. It was a very bad sound! I just hope there isn't damage done to the transmission from this unt going bad.

The car will do ok up shifting, nice and smooth as you would expect. But when I would let up on the gas and coast to a stop it would downshift with a loud metal-to-metal sound. It was not what you would expect to hear from any transmission. It was not a synchronized operation.

This unit is computer tested. Mine failed the test, they replaced it and all was ok, until about 10K miles went by and now it is doing it again.

In Pennsylvania, north of Pitts.


#6 Guest_juancolorado_*

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Posted 19 June 2003 - 06:52 AM

Hi commuter,

I bought this 4cy/auto 2000 Outback wagon new and the "clunk" started about 10k into my owership.

I live on a "dirt" road and the car experiences a lot of rough surface every day. The noise is related to the hitting of these bumps for sure. So I have been focusing on the suspension system, but you mentioned the power stearing unit. I can feel this "clunk" in the steering wheel. The feeling was like there was slack in the steering, as if a bushing was bad. So maybe there is something there to look at. I have gone over this car, laying under it for hours looking at nuts, bolts, etc just trying to find anything that may be loose. But nothing that I can see.

I talked to friend of mine (not a subaru owner) and he said his Toyota did the same thing. I got in his car and listened to it and it sounded the same. He told me he took his in to the Toy dealership and they told him it was the strut action!!!!! So, yes I agree with you, if the mechanics can't find anything then "strut action noise" will take car of the customer!! :-))

Interesting to note is this usually happens below 30 mph. Higher than that and it disappears. Since nothing has fallen off I guess I will just have to live with it, but it sure sounds bad.

Thanks for your reply. I was not finding many answers out there about this. I go in the shop next weds and they will again try to find it!!!!


#7 Guest_juancolorado_*

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Posted 19 June 2003 - 06:55 AM

Mine is also at slower speeds, below 35 mph. It is especially noticeable at "parking lot speeds" as you say. Mine is more of a "clunk", metal to metal noise as if a bushing that holds the strut on is bad, or gone.

Beats me what it is. I hate it, but the wheels are still on and it gets me home!!


#8 Guest_juancolorado_*

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Posted 19 June 2003 - 07:51 AM

I found this doing a "google" search. Interesting to note that they refer their readers to this BB.


Steering rattle


Description: Loud thunking and/or rattling coming from the steering or suspension components during turns into a road depression, such as a driveway or off the pavement to a highway shoulder. In some cases it may be felt in the steering wheel.

Affects: 1995 to 2000 Legacy & Outback, or any 90s Subaru with the rack & pinion steering system.

Diagnosis: Current theory states that it is caused by components internal to the rack & pinion steering system shifting as the suspension absorbs the bump.

Reported solutions: No official solutions. Dealers usually say the sounds is "normal." One owner has found that spraying a rust preventative on the suspension components deadens the sound.

Detrimental effects: None known.

#9 RustyScoop


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Posted 12 August 2005 - 04:41 AM

I have the same problem when turning while going over bump, it make clunk noise in the right rear strut, I suspect it is a strut mount going out. I am taking mine in for check up with my mechanics tomorrow, hope he can tell what's going on. I will post it here later. Good luck guys.

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