Problem with "Shudder" Under load

Hey Guys.... So I've done some reading trying to narrow down potential causes for this, but I can't come to any clear determinations

All of the sudden about a month ago, I've started to experience a slight "Shuddering" problem with the legacy and I don't even know where to START with what it could be.

Scenario: The car runs pretty much perfect under normal or light "Load" And when I say load, thats relevant to not only throttle, but incline.... Now the problem I'm seeing, is as I accelerate off of a line, almost 100% of the time going UP a decent terrain elevation (Overpasses, hills etc...) I will get perfect shifts out of 1st to 2nd, but coming OUT of 2nd Into 3rd, I am getting a "Shudder" throughout the vehicle??? No idea why this is happening, and I'm really concerned it's something wrong with the drivetrain/transmission/torque converter etc... Keep in mind, the only time I really get this shudder between 2nd and 3rd going up slight inclines, is when I'm accelerating with Mediocre throttle "Not slow and easy, but not flat out by any means" A decent consistent boost, coupled with terrain "Load"... Any feedback on this would be AWESOME! Because at this point, I'm a bit discouraged about what it could be.

As a side note: I've seen people make references to spark plugs etc... And while I guess anything is possible and there's MANY of you that know MUCH more then I ha... I guess I would just be shocked to know that something like that could cause such a vehicle shudder.

But I should note, that ironically the spark plugs WHERE just replaced with the OEM NGK's... in August.

Other mentions: The vehicle is more or less stock, no tuning, a K&N filter and 84,000 miles. The trans WAS replaced by the dealer back at 54,000 miles.

Also: When I DO engage the throttle relatively heavy or full out boost, in automatic mode, the shudder does not surface. Also when using the Shift tronic method of shifting, also do not feel the shudder take place....?

could be bad gas.


I had a similar issue with my torque converter where light throttle in 3rd/4th at 40-50mph it would shudder/vibrate, but when throttling up it would go away. This is the tc trying to lock. It ended up going away on it's own. I did a tranny drain/refill and all is well.

Hmmm.... Definitely appreciate the feedback... Yea this literally JUST started, and I've filled up MANY times since... I'm getting NO warning lights either... and like I said, my guy just replaced the plugs in August with new NGK plugs...

So your really thinking this could be a bad tune from the ecu? Just really surprised it's showing up at this point...?

well, i edited my post because I realized you said it just started happening. as long as the plugs were replaced with oem or 1 step colder you should be fine in that department.

I may just say SCREW IT and do a trans refill/flush and see how things go... I also just called the dealer, and they had like 12 things to say about it! lol... Ugh... Potential Sensor this, that, the other... This blows... This car was supposed to be my long term project and stay healthy... this situation is a bit discouraging if it's ANYTHING BUT a sensor of some sort!

I got a buddy cert mechanic buddy of mine, thats gonna hook it up to a diagnostic to see if it's throwing any codes... but knowing my luck, it's NEVER that simple! =/

why are you yelling

Whooo sa... Whooo sa...

Stupid Car.

It sounds like the torque converter having issues engaging. Before you drain and fill the trans make sure that the fluid level is correct. You might be low or high, which can cause numerous issues. Always make sure it is checked on a flat surface though. The dealer may have under filled the trans when it was replaced and now that the fluid is old you are seeing a problem. I could be completely wrong but its possible.

-Jake

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my 07 does the same thing from time to time. I used subaru hp fluid only drained and refilled with 4 bottles helped still there sometimes. Pretty sure i have a intake leak though because the maf and map play a important part in controlling the transmission.

Originally Posted by ericem

my 07 does the same thing from time to time. I used subaru hp fluid only drained and refilled with 4 bottles helped still there sometimes. Pretty sure i have a intake leak though because the maf and map play a important part in controlling the transmission.

good point, I don't think I even realized that when I had my problem. Perhaps those played a role, dirty maf sensor can cause similar issues...and can a post-maf air leak

Yea... gonna recheck trans levels... And have my buddy run the diagnostic for any potential codes, and then maybe try a reflash of the Ecu... This is pissing me off! Of all the nonsense I've dealt with, with the legacy the drivetrain has ALWAYS been rock solid! =/

Relax hulk hogan, it's not that big of an issue. lol. the majority of the threads in this part are of blown turbos and spun bearings. a little stutter isn't going to make babies cry.

yea... Ya know what my biggest concern is though... Is the longevity factor... I really have been making a relatively consistent effort at staying ahead of any and all maintenance to keep this car running for the long haul.

Hate to say it, but me and the fiance' are pondering upgrading her car to an SUV and getting the new Jeep Cherokee Limited... And I may end up trading the GT in on it

But if I do, I may pick up something simple like one of the new impreza's or something to replace her car for me... I've owned a LOT of cars... And I get REAL nervous when problems start popping up... I also think what makes me MOST nervous, is that it's taking place on a transmission thats already been replaced...

Here's a question for you guys...? Ignorance within this drive train I will fully admit openly... But with the trans... lets just SAY it's the Torque Converter... Is this something that can be serviced/replaced without tearing the trans apart and replacing everything?

You shouldn't get REAL nervous, you just need to go to the RIGHT people

Yea for sure... Just gotta figure out who those people are ha... God knows I'm NOT a fan of the local Stealership.