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Old 03-31-2008, 02:40 AM   #51
Sub!eDr!ver
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Location: Atlanta, GA, USA
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2016 Kia Sedona
Tribeca LGT LGT Justy

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Nah, too expensive. It'd be cheaper to add something to what I've already got.
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Old 04-04-2008, 11:37 AM   #52
Trexim
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My 4 week old 08 Tribeca has just developed a strange gear shifting problem, hot or cold. When going from a complete stop (intersections), it would have a jerk when shifting from 2nd to 3rd (guessing). Very annoying. As if it's skipping something. Not all the time, but a majority of the time (4 out of 5 times). I am not sure if it's the same as anything described here. A little bit less noticeable if I put it in Sport mode.

Anyone has any idea? Is it fixable?
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Old 04-04-2008, 11:46 AM   #53
Sub!eDr!ver
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I have noticed that on occasion. Not very often though.

I first noticed it when in Sport mode, but later experienced it in normal mode, so I don't think that the mode makes much difference. Mine is infrequent enough to not worry about it, but it sounds like you might want to check in with the dealer. There might be something amiss.

Does it happen more often when you're changing throttle positions during a shift? It might be the TCU getting confused.

I wonder if trying manual mode would make any difference... Shift manually for a while and see if it happens there.
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Old 04-04-2008, 11:57 AM   #54
Trexim
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Quote:
Originally Posted by Sub!eDr!ver View Post
....
Does it happen more often when you're changing throttle positions during a shift?
...
Thanks for the quick reply. Please forgive my "n00bness", but what does it mean in n00b language? Thx.
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Old 04-04-2008, 12:44 PM   #55
Sub!eDr!ver
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I was just asking if you change your foot pressure on the gas pedal while accelerating.

The TCU is the Transmission Control Unit - a computer that measures various things like gas pedal position, vehicle speed, etc. to determine when to shift the transmission.

I'm not an expert on the TCU, so I'm just trying to theorize what might cause abrupt shifts, so I guessed that maybe the TCU is trying to deal with ever-changing conditions, and may sometimes get confused.

When accelerating from a stop, if you hold your foot in one position, and you'll feel the transmission shift up from gears 1 through 5. The point when it shifts is determined by the TCU, based on many factors, including the position of gas pedal.

If you press the gas pedal down further just before the TCU was going to shift, it may choose to delay the shift until a higher RPM, or if the TCU has already started to shift, it may cause an abrupt shift, because it was already in process when the throttle input changed. It saw your call for acceleration and decided to get the job done in a hurry rather than at its normal pace.

Not being a mechanic, I can't give specifics on the transmission or TCU, but I know computers, and they're not perfect. They try to make the best decision they can based on the information they have available. When that information is constantly changing, they can sometimes make less-than-optimal decisions.

On the other hand, if your tranny is making consistent less-than-optimal decisions, it might indicate there is a real problem.

On my '98 Legacy, my 1-2 shift was always abrupt, and the 2-3 shift was always leisurely. The local Subie shop had no idea why, and couldn't fix it, so I figure there may have been a fault during assembly that caused it to behave oddly. Maybe you have something like that.

Have your mechanic take it out for a drive to replicate the problem. That should help them to narrow it down.
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Old 04-07-2008, 07:01 PM   #56
Capeachy
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Quote:
Originally Posted by Trexim View Post
My 4 week old 08 Tribeca has just developed a strange gear shifting problem, hot or cold. When going from a complete stop (intersections), it would have a jerk when shifting from 2nd to 3rd (guessing). Very annoying. As if it's skipping something. Not all the time, but a majority of the time (4 out of 5 times). I am not sure if it's the same as anything described here. A little bit less noticeable if I put it in Sport mode.

Anyone has any idea? Is it fixable?
I've also noticed the same thing happening on my dad's 08 Legacy GT while shifting from 2nd to 3rd. Stead on the gas the whole way. It's repeatable if I keep the tach at at least the mid 3k rpm range. More noticeable on the sports and sports # shift mode, although I've caught it happen at least once or twice on Intelligence mode.
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Old 04-19-2008, 09:58 PM   #57
my1stsubaru
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A quick up date on my problem of hard shift between 2nd and 3rd gears. I took my tribeca back in to the dealer again. This time they reprogramed or flashed the tcu. Apears to have worked this time. Shifts smooth as when it was brand new. I think this took care of it this time.
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Old 04-19-2008, 11:08 PM   #58
Sub!eDr!ver
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Glad to hear it. Now we know for future reference if ours start to do that.
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Old 11-11-2017, 05:46 PM   #59
lutek34
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I have '08 Tribeca with harsh 2nd to 3th shift. I'm thinking to connect to FreeSSM and clear memory 2 of TCM, but service manual direct to do learning control after clearing memory 2 and this involve connecting to SSM III, lifting the car and run the procedure on SSM. Did any of you just simply drive the car after clearing memory 2 and TCM relearned the values by its self?
I will appreciate any help
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