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3.6R Bipolar transmission

PostPosted: Fri Mar 05, 2010 9:22 am
by CRFaig
Has anyone experienced a delayed and very harsh downchange to first in 'S' mode in full auto (not selecting manually) on the 2010 Liberty?

Driving conditions: Decellerate from 60+Kph down to 20-25Kph on throttle roll-off. (basically, approach an intersection)
Moderately apply the throttle (not quickly. Scenario, intersection is clear and I now want to accellerate through it)
There is a hesitation in throttle response and a friggin hard down-change to first which thumps through the drive line.
Can replicate it easily and has been doing it since new. car has now travelled 1000Kms
Anyone know of a firmware revision on the PCM for the late 09 early 2010 build Libs that has been released via Subaru's dealer network to counter throttle control/transmission control issues?

Re: 3.6R Bipolar transmission

PostPosted: Fri Mar 05, 2010 9:43 am
by smythie
Don't know but I would suggest taking back to a dealer for a warranty fix. Take a service tech for a drive, describe to him what you are doing as you do it and watch the look on his/her face when the 'box kicks down

Re: 3.6R Bipolar transmission

PostPosted: Fri Mar 05, 2010 10:35 am
by CRFaig
Thanks Smythie. Good advice and I have sent off an email regarding it and a couple of other things to a dealer just now.

Still like to know whether anyone else has encountered this in the 2010 model

Re: 3.6R Bipolar transmission

PostPosted: Sun Mar 21, 2010 4:04 pm
by BUDDAH
CRFaig wrote:Has anyone experienced a delayed and very harsh downchange to first in 'S' mode in full auto (not selecting manually) on the 2010 Liberty?

Driving conditions: Decellerate from 60+Kph down to 20-25Kph on throttle roll-off. (basically, approach an intersection)
Moderately apply the throttle (not quickly. Scenario, intersection is clear and I now want to accellerate through it)
There is a hesitation in throttle response and a friggin hard down-change to first which thumps through the drive line.
Can replicate it easily and has been doing it since new. car has now travelled 1000Kms
Anyone know of a firmware revision on the PCM for the late 09 early 2010 build Libs that has been released via Subaru's dealer network to counter throttle control/transmission


control issues?



Yep the loan car I had 2 weeks ago did the same felt like I ran over a house brick think it comes standard with the new auto transmission :roll:

Have you noticed the "DEAD" spot when coming out of a corner or round about when you hit the throttle and fuzk all happens for a second then the transmission takes up and you off again?

Re: 3.6R Bipolar transmission

PostPosted: Sun Mar 21, 2010 9:38 pm
by GTSPECB STI
Subaru's drive by wire throttle is well known for producing this effect, the Yanks called it the stutter. A good tune of the ecu can fix that for GT's but no idea what can be done if you have a N/A Lib.

Re: 3.6R Bipolar transmission

PostPosted: Sun Mar 21, 2010 9:46 pm
by coyote
GTSPECB STI wrote:Subaru's drive by wire throttle is well known for producing this effect, the Yanks called it the stutter. A good tune of the ecu can fix that for GT's but no idea what can be done if you have a N/A Lib.


That's not the DBW, it's the Closed/Open Loop Delay.

Re: 3.6R Bipolar transmission

PostPosted: Mon Mar 22, 2010 11:04 am
by Posseltperformance
I thought this was common to must Subies. My MY06 3.0RB displays similar characteristics.
I think you just learn to drive around them. I'm constantly telling my car "jeeez, settle down" cause of the nasty kickdown. As for the throttle delay I tend to get on the gas earlier than I have with any other car.

Re: 3.6R Bipolar transmission

PostPosted: Mon Apr 26, 2010 11:37 pm
by skyva
I test drove the new outback 3.6 auto last week (build date 01/10 I think). It had a pronounced lag when pressing the accelerator peddle, particularly from 20kmh+. I read on the US legacygt forums that the 3.6's over there have been reflashed under a tsb however the sales rep here told me no tsb has been issued here. It is the only thing I don't like about the car. I might email subaru OZ this week to find out what is going on.

Re: 3.6R Bipolar transmission

PostPosted: Fri May 07, 2010 10:54 am
by CRFaig
Spoke with the head of Subaru Technical here in Australia regarding this issue.

According to Subaru, this excessive shift-shock on down change to 2nd is especially bad when the vehicle is cold but can/does occur when at normal operating temperature. It is common to the 3.6 R and the GT's in the Liberty range.

Because I was able to replicate the driving style that brings on the hard down shift, my local dealer had my vehicle data-logged at the request of Subaru Aust. so that the data can be reviewed at a higher level.

Unfortunately, the shift-shock, while being able to be driven around, handicaps the driveability severely; especially in suburban driving cycles.

Re: 3.6R Bipolar transmission

PostPosted: Fri May 07, 2010 1:22 pm
by Hobber
I read somewhere (possibly on LGT.com) an Australian saying their dealer said the ECU update for the 3.6 was now available in Aus...

Re: 3.6R Bipolar transmission

PostPosted: Fri May 07, 2010 3:21 pm
by swingn
Just sounds like a typical auto to me :P

Agree with Symthie, take it back to Subaru & get them to look at it if it is really a major conseren... Figurers crossed you'll be able to make it fault when taking the technician for a drive :)

Good luck with it mate.

Re: 3.6R Bipolar transmission

PostPosted: Fri May 07, 2010 11:32 pm
by skyva
CRFaig wrote:
According to Subaru, this excessive shift-shock on down change to 2nd is especially bad when the vehicle is cold but can/does occur when at normal operating temperature. It is common to the 3.6 R and the GT's in the Liberty range.


My feeling from a short test drive and investigation on forums was that the shock was due to the throttle being pressed partially, wherein the driver expected acceleration. Due to the lag, no acceleration was detected for around 1 second, whereupon the driver pressed harder. The engine then starts to respond, but to the full throttle input, causing rapid change down in gears and increase in torque, sending a shudder through the drive line.
When decelerating, the drive line has a small amount of play and negative torque transmission, during hard acceleration the torque goes from negative to positive, causing slap and a shudder combined with a drop in gearing, making the car lurch forward.
This is not what I expect from a typical auto tranny, except perhaps from the old holden commodore tranny when transitioning from coasting to full throttle. I would hope that a car built in 2010 would not have a problem that was considered bad in 1995.

From what I have heard removing the lag removes this problem.

Anyway good luck and please keep us informed, particularly if it turns out to be some other problem.

Re: 3.6R Bipolar transmission

PostPosted: Sat May 08, 2010 8:11 am
by Arith
skyva wrote:From what I have heard removing the lag removes this problem.

That's a good excuse for a tune! :D