Intermittent hard shifting

[romeyromes]

Hey guys, newbie here!

Just wondering if anyone has experienced what am I currently going through and if there is anything I can do about it. Feeling pretty hopeless right now. I have a 2007 Subaru Legacy B4 with 93,000km's.

Basically, it started with a P1710 fault code. The car would intermittently shift really hard as if another car was hitting me from behind then will go into limp mode. After a few minutes in limp mode, the car would fix itself and start driving perfectly again.

So I got this fixed by a tranny specialist here in Auckland, Auto Trans. P1710 is a Torque Converter Turbine Speed Sensor 2 malfunction. Luckily I am still under warranty.

Once fixed and after a couple of days driving like a dream, the hard up shifting is happening again. But now, the hard up shift only happens right after start up and when the car is cold. After a few minutes, it will again fix itself and drive perfectly. The tricky part is, it doesn't always happen!

I went back to the Tranny Specialist, no fault codes found and because the hard up shifting is so intermittent, they cannot easily identify the problem.

Has anyone experienced this? Any input would much appreciated.

Cheers guys!

Rome

[ADIKT]

 romeyromes said:

Hey guys, newbie here!

Just wondering if anyone has experienced what am I currently going through and if there is anything I can do about it. Feeling pretty hopeless right now. I have a 2007 Subaru Legacy B4 with 93,000km's.

Basically, it started with a P1710 fault code. The car would intermittently shift really hard as if another car was hitting me from behind then will go into limp mode. After a few minutes in limp mode, the car would fix itself and start driving perfectly again.

So I got this fixed by a tranny specialist here in Auckland, Auto Trans. P1710 is a Torque Converter Turbine Speed Sensor 2 malfunction. Luckily I am still under warranty.

Once fixed and after a couple of days driving like a dream, the hard up shifting is happening again. But now, the hard up shift only happens right after start up and when the car is cold. After a few minutes, it will again fix itself and drive perfectly. The tricky part is, it doesn't always happen!

I went back to the Tranny Specialist, no fault codes found and because the hard up shifting is so intermittent, they cannot easily identify the problem.

Has anyone experienced this? Any input would much appreciated.

Cheers guys!

Rome

Get in contact with a authorized subaru dealer/ mechanic who can upload the new PAK files for the auto trans (sublab in east tamaki do it)

I assume its a 5 speed - and its doing it from 2nd to 3rd??

I will find the thread with more info - hang tight

[ADIKT]

Read this: http://clubsub.org.nz/forum/showthread.php?47337-PAK-file-firmware-for-your-auto-trans

Welcome BTW

[romeyromes]

Thank you! The link would be much appreciated.

I'd say 2 to 3 would be the hardest shifts while the tranny is playing up. But overall, all gears shift pretty hard.

[Kiwi_Fozze]

Yep, reflash pak file and tcu reset will sort you out. Mine was really bad, but after getting gull fluid flush done and tcuu reflash/ reset its really nice.

Get the occasional thump into 3Rd bit I think thats a tcu reset to fix it

[romeyromes]

Cool thanks, will give them a shout as soon as I can.

The only weird thing is tho, my gears all change SMOOTHLY when the tranny is NOT playing up..

And when the tranny IS playing up, the gears change violently rough. Like really bad!

Edited January 25, 2016 by romeyromes

[Kiwi_Fozze]

When was the last time the trans fluid was changed?

[romeyromes]

Last week, Wednesday.

[Kiwi_Fozze]

So yeah, next thing I would be looking at is getting the tcu reset, and if that doesnt do it then a pak file update.

I know it was a fairly common iissuewith the legacies

[romeyromes]

Cool, thanks man. Will get onto it.

I've only had the car for less than two months, very unfortunate but I absolutely love it so am reluctant to reject the car just yet.

[SubLeggy]

im in the same boat i think. when changing down from 4-3 gear the whole car does a thump/jolt kind of move. seems to to do it when it is at a certain speed when changing down... and also when changing from 2-3 gear it will do a thump as well. changing up gears 2-3 is when i use the paddle shift on the steering wheel(giving it a slight bit of stick) and when changing down into 3rd gear is when its doing it automatically.

looking at getting the gearbox serviced with fresh oil and filter as im not to sure when it was last changed. i think ill also look into the pak files etc

[romeyromes]

Are you getting slight thumps where the car is still easily driveable?

I'm getting thumps so hard that I cannot continue driving until it goes away, and it usually does. But only a matter of time until it happens again.

[killervq30de]

I started this thread. Mine was when driving normally and on part-throttle the 2nd to 3rd shift was a firm thump. You'd expect the thump if wide open throttle as it uses full line pressure to prevent slip. I never had it on downshifts. And was intermitent as well, I notced but never thought much about it. Sublabs picked it up when testing driving before a service.

[SubLeggy]

Only get thumps/jolts when its slowing down e.g braking or just rolling and it changes into 3rd and in 3rd for a couple of seconds and then it thumps/jolts. But wont do it if im changing the gears e.g tiptronic/paddle

[romeyromes]

Fixed.

Apparently the the Turbine Converter Speed Sensor 2 that was previously replaced was faulty. Live data showed no feedback during cold start up.

It is known that this sensor is attached to the valve body so the valve body will also need replacing if this sensor needs replacing.

So I guess Auto Trans in Newton Rd Auckland can replace this sensor for a few hundred dollars rather than spending at least $2000 for a new valve body.

It is kind of a short cut job but hey, if it works, it works.

[romeyromes]

Sadly, I am mistaken.. Violent harsh shifting occurred again over the weekend.

It is clear that this sensor cannot be replaced by it self, the valve body MUST be replaced.

I am now dealing with Transmission Solutions, who are now in the process of ordering a genuine valve body from Japan.

[ADIKT]

 romeyromes said:

Sadly, I am mistaken.. Violent harsh shifting occurred again over the weekend.

It is clear that this sensor cannot be replaced by it self, the valve body MUST be replaced.

I am now dealing with Transmission Solutions, who are now in the process of ordering a genuine valve body from Japan.

Did you ever have the new PAK files loaded?? I would be doing this before spending money on valve body

[Kiwi_Fozze]

This

And if you are doing the whole valve body, theres an outfit in the states that do valve body upgrades (faster shifts) for a similar cost

[romeyromes]

 ADIKT said:

Did you ever have the new PAK files loaded?? I would be doing this before spending money on valve body

No, I didn't get the chance to.

And I'm under warranty and the dealership is paying for my excess so I haven't spent a single cent.

Still frustrating AF tho..

[Kiwi_Fozze]

Before the gearbox is pulled out, reflash the pak file. Its a known issue. Its a known fix. Its $60. Its a half hour job if that.

Tell your workshop that all work must stop until the known issue, and factory issued repair (reflash) is done

[romeyromes]

This is the thing, when the car has warmed up nicely.. the gears shift smooth as silk. For all gears, up shifts and down shifts.

When the car is cold, I get symptoms of a failing valve body. Delayed shifts. Violent violent shifts (Wish I could emphasize this even further haha) but when my mum was in the car when it happened, it scared the sht out of her lol.

The car is not in driveable condition while it is cold.