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Discussion Starter · #1 ·
Hello. Recently bought a 2010 Forester X Premium automatic and after a couple months of driving it I have noticed something a little odd with the tranny.

When accelerating at a little below normal I have noticed that at the 2nd to 3rd shift it will bog for a moment, like a manual in too high a gear, then after a second will bump a few hundred RPM and be normal again.

I have also noticed that if I come to nearly a stop and then accelerate again, for instance when doing a 'Michigan Turn' on the highway (like a 180 to go the other way through the median) it acts the same, like it is in high gear yet and bogs. If I give it a little more accelerator it goes away.

Transmission fluid is still looking decent, light red yet, no signs of breakdown, but I also don't know when it was serviced since it was bought used with 100k miles on it.

Any advice on what to look for?
 

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2017 Forester XT Touring CVT
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Not knowing the entire service history of the car.

I would say that based on your description and that the tranny fluid bright red,
that it may not be a tranny issue at all. i would of course check the fluid level just to be safe first.

Procedure:

Drive the car on a 20-30 min loop, best if you drive to a highway go one exit and then drive home. The point is to get the tranny fluid up to normal temp.
With the car running on a flat and level surface remove the tranny dipstick wipe and insert then pull out. level should be in the hot range.

Now that this simple thing is out of the way. I suggest pulling the intake off the throttle body and looking at the throttle body butterfly valve. it should be nice and clean.
If not, clean it using throttle body cleaner. before cleaning atleast unplug the connector to the throttlebody actuator.

FYI, it is much easier to do this job by unplugging the battery and removing the throttle body from the car and cleaning on the bench.
look in the intake manifold while doing this it may be very dirty and oily. this would indicate time to do a intake cleaning. CRC makes a great product call GDI Intake valve cleaner, some shops will also do the service with a BG kit and Chemicals for around 100-150$.
your choice. For 200$-250$ a local good honest mechanic will remove the throttle body clean it and do the intake cleaning as well.

Just make sure that the throttle body gasket is replaced, they are one time use. and get the Genuine subaru part.

after doing all this change the air filter and follow the online procedure posted on this forum for doing a throttlebody relearn.

Make sure the battery is disconnected step on the brake peddle a few times and the leave the battery disconnect for over 30mins.

Link: https://www.subaruforester.org/threads/how-to-idle-re-learn-after-battery-disconnect.154161/

If this does not work or make anything better, then go to a subaru dealer and ask them if there is a TCM Software update that is associated with your symtoms. they may charge you and hour of labor to do the update.


Last thing if a throttle body service and induction cleaning has not yet been done to this car, 100K miles would make it well over do.
 

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Discussion Starter · #4 ·
Thanks for the info. I will add the throttle body cleaning to the things I will be doing along with the timing belt kit and front brakes.

I am not doubting at all, just curious how the throttle body could be causing a shifting issue? Or do you think the engine is not at the right RPM when the transmission wants to shift?

Appreciate it!
 
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