This is for a '95 4EAT.

There was a P0758 (transmission solenoid) code that came up somewhat recently. At that time the car was put into "limp mode", 3rd gear only. The transmission solenoid set was replaced with one from a wrecking yard.. The transmission worked again and codes went away.

Several weeks later while driving it is suddenly stuck in 3rd again. In D, 3, 2 it is stuck in 3rd gear, in 1 it barely moves. When selecting R there's a hard shock and it does not move at all. There are no check engine or ATF temp codes/lights.

A hefty leak from a transmission cooler line was spotted, which wasn't there before.

Added plenty of ATF fluid, still the same. Drained the ATF fluid (I read you're suppose to get about 4 quarts), got about 5 from everything that was added. Put back in about 3 qt. and still the same issue.

I don't want to hear that the transmission is toast or needs a rebuild.

 

From the troubleshooting manual, this is what is listed for: Shock occurs when select lever is moved from “N” to “R.”
-Control module
-Accumulator(4A)
-Control valve
-ATF deterioration

 

It's basically the same issue as described here:

 

Edited February 12, 20206 yr by userface

1. Was the 0758 present continuously (it never went away) before you started replacing the solenoids? 

2. Did the 0758 go away when those solenoids were replaced?

3. Has that code, or any others, come back again with the new round of issues?

4. Is the pan dented, damaged, previously repaired or deformed?

5. What was the condition of the old fluid in the pan and the screen at the bottom of hte pick up (essentially the "filter) when you pulled the pan?

My first Q is, does it roll easily in neutral?

On 2/13/2020 at 7:11 AM, idosubaru said:

1. Was the 0758 present continuously (it never went away) before you started replacing the solenoids? 

2. Did the 0758 go away when those solenoids were replaced?

3. Has that code, or any others, come back again with the new round of issues?

4. Is the pan dented, damaged, previously repaired or deformed?

5. What was the condition of the old fluid in the pan and the screen at the bottom of hte pick up (essentially the "filter) when you pulled the pan?

1) Yes. When the code was reset it would come back right away. I think it took two drive cycles for it to display after resetting.

2) Yes, right after.

3) No codes at all since.

4) No.

5) The fluid seemed fine. Three drain and fills were done about 10-20k miles prior. No debris was noticed on either end of the screens. Water was run through it and it came out clear.

1. Did the trans have any symptoms at all before the first code showed up?

I'd go back in and inspect the solenoids, the solenoid orings (if equipped), the internal filter and it's corresponding oring as well.

a. Solenoid replacement fixed the code, and temporarily the drivability problems - suggesting an issue (but maybe not all) was definitively fixed. 

b. "New" symptoms presented after the work...maybe suggesting something that was touched is amiss.  

Maybe another problem is causing debris to foul things over time (hence the slight reprieve), but given a & b above I'd be interested to double check some things. 

On 2/13/2020 at 2:13 PM, CNY_Dave said:

My first Q is, does it roll easily in neutral?

Yes.

2 hours ago, idosubaru said:

1. Did the trans have any symptoms at all before the first code showed up?

I'd go back in and inspect the solenoids, the solenoid orings (if equipped), the internal filter and it's corresponding oring as well.

a. Solenoid replacement fixed the code, and temporarily the drivability problems - suggesting an issue (but maybe not all) was definitively fixed. 

b. "New" symptoms presented after the work...maybe suggesting something that was touched is amiss.  

Maybe another problem is causing debris to foul things over time (hence the slight reprieve), but given a & b above I'd be interested to double check some things. 

Sometimes it seemed it would rev kind of high before switching gears. After the solenoids were replaced the timing of the shifts seemed to be better.

After sitting about a week when putting into R there is more of a clicking sound and does not have the hard shock that there was initially.

I'm concerned gears may have "seized" (if that's something that happens) due to low transmission fluid. Right after the solenoids were replaced the transmission did not work very well. More fluid was added and then it worked fine.

 

Edited February 15, 20206 yr by userface

I don’t know how long or aggressive it was driven but I highly doubt low fluid caused any damage that quick.  I’ve seen lots of subarus without ATF or low ATF and no immediate failures.  

it would be far more likely that al the issues are related to the same pre-existing failure modes which are compounding over time and getting worse.  

The following is from the attached text file, something I found years ago in a Subaru 4EAT Training manual that I borrowed from a friend.

If shift solenoids #1 or #2 malfunction, the TCU
deactivates the other. This results in either 3rd gear or
Reverse (when selected).

4EAT Fail Safe Components and Failure Results.txt

Edited February 16, 20206 yr by Rampage

On 2/13/2020 at 2:13 PM, CNY_Dave said:

My first Q is, does it roll easily in neutral?

After checking again, it does not move in N. It can kind of rock back and forth only.

23 hours ago, idosubaru said:

I don’t know how long or aggressive it was driven but I highly doubt low fluid caused any damage that quick.  I’ve seen lots of subarus without ATF or low ATF and no immediate failures.  

it would be far more likely that al the issues are related to the same pre-existing failure modes which are compounding over time and getting worse.  

Thank you for your input. I'm thinking at this point either the valve body. If not the valve body then something more serious in the transmission. For another set of solenoids to go bad within a few weeks isn't very likely.

On 2/15/2020 at 11:55 AM, idosubaru said:

I don’t know how long or aggressive it was driven but I highly doubt low fluid caused any damage that quick.  I’ve seen lots of subarus without ATF or low ATF and no immediate failures.  

it would be far more likely that al the issues are related to the same pre-existing failure modes which are compounding over time and getting worse.  

Do you have any idea about this:

I idled the engine for 25 minutes, checking the trans. fluid level every five minutes as to get it to the cold checking level the service manual states the engine must be idled for 25-30 minutes when 32° F . I checked it every 5 minutes since it's not near 32° F. After I shut the engine off, with the hood open I could hear a bubbling/boiling sound and then a crackling (not exactly though the best word I can think of) coming from what seemed like where the torque converter is, or from further down in the trans.

Edited February 17, 20206 yr by userface

If it’s what I’m thinking, I’ve heard that sound before. I don’t know what it is though but it’s been on running driving cars that did it for quite a few thousand miles and some would shift funny until you turn the car off then back on and that would usually fix it until the next drive.

My current XT6 is one of them, so far I’ve driven it like 10,000 miles making that noise with no issues. But I’d love to know what it is. 

my suspicion is the torque converter.  But that’s very much a guess. I don’t know they’re failure modes enough. 

I googled “torque converter Noise Subaru” and there are some videos of noises and symptoms listed that seem very close to what we are describing.  I didn’t click on any links but you could give it a try.  

If it is, we then need to know if other issues can cause torque converter noise (bad solenoid, wiring or valve body, poor ATF flow), or if noise always means the torque converter is bad?

On 2/16/2020 at 7:22 AM, userface said:

After checking again, it does not move in N. It can kind of rock back and forth only.

It might be the front or rear diff then. Or a very very draggy wheel bearing.