Jump to content
Ultimate Subaru Message Board

1996 Legacy AT codes 23 and 24, Transmission won't go into gear, car won't move


Recommended Posts

I've always wanted a Subaru and finally got one.  Only took 15 miles to break down... Engine still running great but transmission won't shift into any gear.  Park still works but all other gears are like neutral.  AT oil temp light flashing 16 times, got the crash course on Subaru diagnosis and grounded pin 5 of B82... got back codes 23 (engine speed signal) and 24 (duty c solenoid).  

 

From what I can tell from searching neither one of those codes should cause the transmission to not go in gear correct?  I haven't driven it enough to know if it has torque bind.  I'm not worried about pulling the back of the transmission and replacing the clutch pack and solenoid but the code 23 and different symptoms has me confused.  In the FSM code 23 has a symptom of 'no lock up' which I don't understand either.  Is that what the tranny is doing?

 

I pulled fuse 14 and erased the codes to result in no difference (lights stayed off but the car didn't move) and I put a fuse in the FWD override with no change.  I didn't see a light on the dash for FWD either though... not sure if I was supposed to.  

 

Super clean Legacy, literally the definition of owned by the elderly.  198k miles, unknown history of timing belts, head gaskets but ALL fluids are fresh and full with the exception of the transaxle which has a slight leak but isn't below the low line (no AT fluid that I could detect).  It passed the test drive flawlessly with the exception of the first stop sign with the engine cold the car stalled.  I attributed it to low idle but hindsight is a little more clear.  Transmission code TZ102ZAAAA-C7

 

Please help!  I don't want to replace parts when I should be looking for a new transmission.

 

Thanks, Ben

Edited by bhardesty
Link to comment
Share on other sites

Looking into the troubleshooting section of the FSM I think my symptom is represented by the description: 

 

Vehicle does not start in any shift range (engine revving up).
 
Which has the possible causes of: strainer, control valve, drive pinion, crown gear, axle shaft, differential gear, oil pump, input shaft, output shaft, planetary gear, drive plate, or ATF level too high or low.  
 
Which still doesn't explain the codes 23 and 24....  Any transmission gurus out there?
Edited by bhardesty
Link to comment
Share on other sites

Codes could be artifactsbof another issue and not directly related. Like simply its expecting something to move that isn't.

 

Looks like you checked fluid level?

 

A rare failure related to Duty C issues is the clutch hub/drum shearing off. I would search for what symptoms occur when that happens. I know someone on here has hadn't it happen and posted about it before and years ago I sold someone one off a parts transmission I have. Bigbususa or some user name like that comes to mind.

 

Might need to find the correct name of that part to search. It's the transmission side driven gear/hub that the 4WD bits engage and are driven by. Too much torque bind and it shears off.

Link to comment
Share on other sites

If the Duty C is an artifact and not real then maybe this is less likely but no power to the rear (and maybe the front) sounds like a possible symptom of it.

 

I've gotten borked non-moving 4wd Subaru transmissions to move by revving high ( blown front diffs, bad solenoid issues) but that's probably a bad idea when you don't know, lol.

Link to comment
Share on other sites

check your CV axles. If they are completely broken - inside the rubber boot - not in the diff - they will spin on the TRANS side but not the wheel/hub end. Only takes one broken CV to stop the car - due to the open diffs. Albeit, when this happend on my '96 Legacy it would still @ least move.

 

GL,

TD

Edited by wtdash
Link to comment
Share on other sites

I pulled the top transmission cooler line off the radiator and started it up, no flow.  

 

Fluid level is a little high, I confirmed both CV's and rear drive shaft do not spin while idling in drive or reverse.  I revved up to 3k with no difference.  

 

Does the transmission pump fluid through the radiator when it's cold?  Not sure what other line I can pull to further diagnose the oil pump.  I also don't see anything about transmission oil pumps failing on the forum.

 

The clutch basket/shaft part is called the rear driveshaft unfortunately.  Hard to get the search results I'm looking for especially being a rare failure. The only thread I could find was from a manual transmission with the viscous coupler system.  

 

And don't get me started on the PO...  

Link to comment
Share on other sites

I pulled the plugs out of the TCU putting the car into 'limp mode' with no change.  Seems to me if the rear clutch basket/shaft sheared the front wheels would still drive.

 

Having no flow from to the radiator transmission cooler seems like a good lead.  What is the transmission 'strainer' listed in the FSM?  Seems unlikely but could a filter or something be clogged so bad I am getting zero flow?  Or is this more likely the pump itself? Control valve?  Help with diagnosing further would be great!

 

Could all this be the engine speed sensor?  That's the code 23 I got.  

Link to comment
Share on other sites

You're sure it has plenty of fluid? No evidence that the cooler lines split and pumped all the fluid out while you were driving?

 

Pull the transmission pan off and see if the pickup screen is clogged.

Other than that, no flow would mean either the pump is toast, or maybe something in the valve body has broken.

Link to comment
Share on other sites

Did you remove both hoses or just one?

Should always have flow through the cooler. Possible something in the trans is blocked, but regardless of trans temp or gear position fluid should be flowing if the pump is pumping.

 

 

I forget what the routing is for trans fluid flow. I'll have to look that up again.

Link to comment
Share on other sites

I just pulled the top hose on the radiator. I'll pull the pan tomorrow.  My local U-Pick-It only charges $30 for the transmission control valve so I'll probably throw one of those in next isolating the oil pump if it isn't fixed.  Only have to pull the pan and a bunch of bolts/wires to replace it.

Link to comment
Share on other sites

Pulled the pan this morning, screen looked like new so I pulled the control valve.  Went to the junk yard and found one, removed it, installed it, no luck...

 

Still no flow so is it 100% the transmission oil pump?  Has anybody ever seen this before?  I can't find a thread but most people swap the transmission instead of fix them it seems.  

 

The transmission at the junk yard is from a 1997 outback code TZ102Z2ABA-CH and the transmission in my Legacy is a TZ102ZAAAA-C7.  Is that a clean swap with the same gearing?

Link to comment
Share on other sites

Didn't note your version of the Legacy? Any 4EAT EJ25 from '96-'98 are 4.44; EJ22 w/4EAT are all 4.11. This applies to all Legacy, Forester and Impreza. These will all interchange w/your '96. '99+ are the phase 2 4EAT....no go.

Edited by wtdash
Link to comment
Share on other sites

Somewhere on the side of the trans there's a plug where you hook up a pressure gauge to check line pressure, but probably not much point.

Sounds like the pump bit it, and when those go there's a good chance of chucks metal into the valve body which will be impossible to clean. Pop a used trans in it.

 

Make sure the cooler in the radiator and the lines going to it get flushed.

Link to comment
Share on other sites

Automatics are less problematic than you might think. These 4eats run for 300k easy with nothing more than fluid changes. Some develop the torque bind issue if people have run mismatched tires or under inflated tires for an extended time, but for the most part they're trouble free. 

The manual transmissions have a much higher failure rate. 

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...