[B-Spec]

My transmission in my 98 LGT does the same excat thing.

It comes and goes like that? Mine has been running fine for the past week now. It seems like the harder I drive it the better it is. When its cold and I am just cruising light throttle it gets really bad. Most people would die to have a auto tranny that shifted that positive.. LOL!

 

[elislider]

here's what the guy that bought my car told me, his dealership said there was a special way to reset the ecu that has to do with the transmission and that indeed solved the problem, it's been years and that's what little I remember... Good luck.

I have never heard of this, and that fascinates me. good info. do you have more details? did it take special tools? (subaru select monitor, etc) or was it just a regula ECU reset (pull battery terminals, hit the brake, reattach terminals)?

 

[Sarra]

>_> This sounds like either a problem with a sticking solenoid or something is wrong inside the trans. It could be a computer issue too.

Take it to the dealer and have them fix it.

1) This has NOTHING to do with the Torque Converter. If it was sticking on or off, you would have a stalling when you came to a stop, not the engine revving to 4 grand then slamming into 4th. The Torque Converter has NOTHING to do with when the transmission shifts. If it was stuck in the 'off' position, you would simply burn your trans up since a modern 4 speed (or 5, 6, 7, or 8 speed) generates so much heat in it's final gear with the TC unlocked, there's no way to dissipate all the heat. This obviously has nothing to do with the OP's issue.
2) The transmission is NOT going into limp mode. Limp Mode is I believe third gear. It would be the opposite of what's happening, cruising in 4th then SLAMMING into 3rd, and it would stay there even at a stop.
3) When the car is in third gear, all of the shift solenoids are OFF. Fourth Gear is most likely OFF ON, or OFF OFF ON. Seeing how the last solenoid is only ON in fourth gear, it's possible that it's just sticking, weak, or something similar.

This really isn't something to require a fucking transmission swap over. >_> It's probably a $50 solenoid sticking. Is that REALLY worth the time and hassle of pulling a transmission, going through the work of getting a new one, and swapping it?

 

[B-Spec]

When it does slam into the next gear it also slams when down shifting as well. When I pull up to a stop it will slam into every lower gear until I come to a complete stop.

 

[B-Spec]

Update.

I am pretty sure it is the TCM that is causing the issue. It happened again today as soon as I started up my car. I drove for about 15 miles and it was slamming up and down gears. While driving down the road I quickly turned the engine on and off and as soon as it restarted the tranny was perfect. Been running perfect ever since. That tells me that the TCM reset when the key was off and it somehow corrected itself??.. At least that is what it seems like to me. Any other ideas?

 

[Sarra]

When it's slamming gears, it could be your trans pressure solenoid sticking at 100%, or sticking open. Basically, there's a solenoid that controls pressure through the valve body, to each clutch pack via the solenoids. The higher the pressure, the harder your shifts. The ECU/TCU will command a solenoid via a duty cycle to give a soft but not too soft shift while driving normally.

If the solenoid is sticking, you'll notice it slams after you floor it, or do a hard accelerate, which is when it ramps up the pressure. It might also ramp up pressure and let it drop down when you're cruising to try to keep the solenoid clean.

Having it slam through the gears when you're decelerating tells me it might just be the something amiss with the solenoid, or the computers think the trans pressure is something other than what it really is.

 

[93ImprezaAWD]

hey man i had a 93 impreza fwd that did the same exact thing haha i just drove it like that for a couple years and it was fine just a little annoying i never changed fluids or even really cared to fix the problem because it was an auto and i don't like automatics so i din't care anyways! Plus dude it's a subaru! You'll be fine! hahaha


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[BackWoodsBob]

I DID see a line pressure silonoid (fu engrish I spell how it sounds) wire.... I wonder if it's somehow getting the wrong voltage and increasing the pressure in the trans line causing harder shifts. . .

 

[B-Spec]

I fixed the problem.. Had nothing to do with the transmission directly. I had to replace the entire engine wiring harness all the way to the computer. I replaced every single sensor on the motor and the tranny as well as the plugs, coil pack and countless other things. I spent almost 2,000 bucks in parts and sensors and it still hesitated and slammed gears. Finally I replaced the main engine wiring harness and now it runs like a champ. I also put every single old sensor back on and it still runs perfect. I basically tossed almost 2K out the window. After taking out the main harness I then tested every single wire in it one at a time and I STILL can't find a bad wire in it. No idea what to say there but all I know is that it has been running perfectly for several months now.. New harness fixed it when the old one was not bad.. LOL!!

 

[Sarra]

Well, you tested the harness, but only sorta. Say, if you take a wire, and you cut back the insulation, then cut all of the little strands in it but a few, it will 'test' okay, but if you put 12v with 4 amps through that wire, it's not gonna work.

If, say, that wire was going to a shift solenoid, then you're really in a weird spot. Basically, the computer commands a specific pattern in the solenoids for whatever gear it wants, but if the signal doesn't get there, then, other than an 'unspecified ratio' error, it doesn't really know if it's shifted or not (it should monitor engine speed, wheel speed, etc and figure out it hasn't shifted).

Since it thinks it's in, say, 3rd gear, it ramps up the internal line pressures to keep the clutches firmly engaged. Then, your bad wire wiggles just right, and that solenoid activates, and BAM! You just slammed from second into third.

It could do really hard shifts from third to fourth if it thinks the solenoids are engaged when they aren't, and it commands TCC lockup.

 

[B-Spec]

Well, you tested the harness, but only sorta. Say, if you take a wire, and you cut back the insulation, then cut all of the little strands in it but a few, it will 'test' okay, but if you put 12v with 4 amps through that wire, it's not gonna work.

If, say, that wire was going to a shift solenoid, then you're really in a weird spot. Basically, the computer commands a specific pattern in the solenoids for whatever gear it wants, but if the signal doesn't get there, then, other than an 'unspecified ratio' error, it doesn't really know if it's shifted or not (it should monitor engine speed, wheel speed, etc and figure out it hasn't shifted).

Since it thinks it's in, say, 3rd gear, it ramps up the internal line pressures to keep the clutches firmly engaged. Then, your bad wire wiggles just right, and that solenoid activates, and BAM! You just slammed from second into third.

It could do really hard shifts from third to fourth if it thinks the solenoids are engaged when they aren't, and it commands TCC lockup.

Yes I understand all that completely. Only thing is I didn't touch any of the wiring from the trans to the TCM. Just the engine harness and the only two wires that connect from that harness is the TPS sensor and vehicle speed. Not to mention the fact that I used a car battery as my power source when testing every wire in that harness.

 

[Sarra]

Yes I understand all that completely. Only thing is I didn't touch any of the wiring from the trans to the TCM. Just the engine harness and the only two wires that connect from that harness is the TPS sensor and vehicle speed. Not to mention the fact that I used a car battery as my power source when testing every wire in that harness.

Well, used a car battery... But you still didn't put a load on it. Car battery can put out 400+ amps if you demand it, which would... Yeah.

It could have been a sensor, you removed and jostled it into working again, so now, you really have no idea what caused it. :rotflmao:

 

[B-Spec]

Well, used a car battery... But you still didn't put a load on it. Car battery can put out 400+ amps if you demand it, which would... Yeah.

It could have been a sensor, you removed and jostled it into working again, so now, you really have no idea what caused it. :rotflmao:

I know!!!! It is a stumper. Before replacing the harness I replaced every single sensor in the car so if it was a sensor you would think I would have found it then. Now I have a pile load of new spare parts cause all the old stuff is back on. lolol

 

[Michael 2882]

I fixed the problem.. Had nothing to do with the transmission directly. I had to replace the entire engine wiring harness all the way to the computer. I replaced every single sensor on the motor and the tranny as well as the plugs, coil pack and countless other things. I spent almost 2,000 bucks in parts and sensors and it still hesitated and slammed gears. Finally I replaced the main engine wiring harness and now it runs like a champ. I also put every single old sensor back on and it still runs perfect. I basically tossed almost 2K out the window. After taking out the main harness I then tested every single wire in it one at a time and I STILL can't find a bad wire in it. No idea what to say there but all I know is that it has been running perfectly for several months now.. New harness fixed it when the old one was not bad.. LOL


Want the bad news? Chances are it was just a dirty body earth! Subaru uses aluminium crimps on all there body/chassis earth termination points and it doesn't take much to get but metal corrosion between the two. Just remove all the earth's clean them up or replace the terminals and wire brush the area or bolts too and job done no more voltage drop caused by a bad earth point. It's nothing to do with the battery terminals either btw because of the rubber mounts (engine trans and exhaust etc) there is wire that earth all those components to the bodie or chassis they are the connections that get corrosion between them.