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Odd transmission shifting behavior after duty-c swap.


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I just changed the duty-c solenoid and valve body on a '98 Forester (did a drain/fill at the same time) and now the AT-Temp light is out and the TCU is happy but once it warms up the transmission shifts hard and at some speeds/throttle posistions it can't seem to decide which gear it wants to be in so it bucks back and forth between two gears for a few seconds. Really odd behavior. The torque bind is gone or at least reduced to what I consider normal levels.

 

I can't say for sure if this behavior started before the duty-c change but I would think the owner would have mentioned it. I'm guessing this has more to do with changing the fluid than it does the duty-c because AFAIK the duty-c only controls the clutch pack lockup which seems to be working just fine. What I'm getting seems to be gear switching or TC locking/unlocking or both.

 

Will the trans-x additive that people talk so highly of help with this?

 

Could I have done something durring the duty-c change that would have affected this?

 

Fluild level is good, color is normal, etc. My drain/fill replaced about 1.5 gallons of fluid - a bit more than usual because I lowered the back of the tranny and pulled the extension housing off for the duty-c change.

 

GD

Edited by GeneralDisorder
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The drain/fill came up heavy on the fill end because I left the back off the transmission overnight with the tranny cross-member off. I had to put in about 6 quarts. Yes I did check it while idling and hot after driving. The fluid level is spot on.

 

GD

 

 

lol! OK, makes sense. I didn't mean to imply you didn't know what you were doing, just confused on the fluid amount.

 

 

What type of fluid do you use? If it's the same you've had luck with in the past, doesn't seem like that could be a problem. Is it possible the tranny had the wrong fluid to begin with and the 2 types don't play well together? maybe 2 more drain/filss would help.

Edited by 1 Lucky Texan
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lol! OK, makes sense. I didn't mean to imply you didn't know what you were doing, just confused on the fluid amount.

 

I didn't think you were implying anything - figured you were confused because I said gallons in the first post instead of the usual quarts these are rated in.... just want to be clear on what I have done and how I've done it. Best to state it explicity so there's no confusion.

 

What type of fluid did you use?

 

Valvoline Dex/Merc generic fluid.

 

GD

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Is it possible the tranny had the wrong fluid to begin with and the 2 types don't play well together? maybe 2 more drain/filss would help.

 

Hhhmmm - yeah I use this fluid all the time because I can get it in gallon jugs. Never had an issue.

 

He just picked up the car and I talked with him - the hard shifting and such was already going on so actually this may have not had anything to do with my fluid change.

 

On that note - will the trans-x help at all? It doesn't slip.... just shifts all wacky, delayed up-shifts, flagellating between gears, and hard shifts.

 

I really don't want to have to replace the tranny on this thing. I bought it with a fubar 25D which I replaced with a 2.2 that runs great. I'm going to take a bath on it if I have to do the tranny also. You would think that a '98 with 147k and bad 25D for $800 would be a good deal.... but this one I'm not so sure about :(.

 

GD

Edited by GeneralDisorder
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i asked an independent tranny shop about my 97 GT hard 1-2 shift. he asked about the mileage, 155k and responded with, ''at that mileage just rebuild it.'' of course he would , that's his business.

 

he then commented that to really know what is going on you have to know what info is being sent to the trans. is the TPS sending good / accurate info. is the TCU good. and i don't know what else.....

 

so it is either the TCU sending bad info, or the solenoids not able to do what they are supposed to. that's my guess any way.

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Trans-X AT additive is best known for fixing 99 & 00 models that develop a lazy delay problem of shifting from R to D. I don't think it would be a good product to fix your problem.

 

I am not sure I understood the chatter conversions in earlier posts on this thread. It is important to know that the AT dip stick takes only 1 pint of ATF to fill from bottom hash mark to top hash mark. Because of that, it is just so easy to over fill.

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How about a bad throttle position sensor?

 

Actually I had that same idea. I also noticed that the TPS reading was really odd at ide. As in it never read 0% on my scanner. I need to check into that further. I just had a '98 Legacy with the same engine (Forester has a 2.2 swap) on my scanner and it was reading 0% at idle from the TPS. It shifts smooth as butter.

 

In fact!! The car in question that was on my scanner today is the car the 2.2 in the Forester came from and it shifted hard when it was in the Legacy also.... the engine I put in it's place is from a '95 and runs and drives great....

 

Confused yet? :-p

 

I'll have to look into this closer for sure.

 

GD

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Ya, it should definitely read 0% on the TPS at idle.

Both my old 96 and my now 98 do that.

 

Is the throttle held open at all? If you start the engine with up to about 3% throttle opening it will actually idle down to 700 RPMs, and the TPS on my scan tool will jump down 0%. The computer has some built in calibration for the TPS, the IACV then takes over and makes it idle right. If you start it with 3%, after it idles down let off the gas and it'll stall. But if the throttle is always held a bit open, or messed up, the ECU will probably correct for it, while the TCU might just get pissy about it.

 

My auto tranny will occasionally hunt a little bit, but ONLY when I considerably change throttle input while it's shifting. Usually results in a really hard BANG.

Mine has 243k on it, so that's not too surprising...

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ground ground ground check them all there was probly one atached to the soiliniod you changed there is one on top right side of intake check them all sounds like your electroincs are trying to ground thorgh the shaft bushings or the forward clutch pack has to mutch clearance anting that very inconsistant is caused by electronics not being grounded proper

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