Change automatic gearshift points ??

[howpow]

Hi Folks. I have a 2008 2.5i Liberty (Legacy) with the 4 speed auto. The car has only done 20,000 klms so is in as new condition. One thing that annoys me is that no matter how gently I accelerate it holds both 1st and 2nd gears to nearly 3000 rpm before changing and has done this since new, which is far more than neccessary. When I mentioned it to the service guy he said that they would reset it. No Change! It annoys me so much I tend to drive it using the slapstick most of the time.

 

I guess my question is are the change points able to be reprogrammed and if so can my Subaru dealer perform the operation?

 

Thanks in advance

[Legacy777]

I would venture to guess your local subaru dealership could possibly adjust them. I know on the older cars, they couldn't, but the newer ECU's are alot more friendly for making adjustments like that.

 

So I would suggest giving them a call and see if it is something they can do.

[Gloyale]

One thing that annoys me is that no matter how gently I accelerate it holds both 1st and 2nd gears to nearly 3000 rpm before changing and has done this since new, which is far more than neccessary.

 

You do know it is a Boxer 4 cylinder? Not a big V6 or V8?

 

Considering that the engine doesn't make really anywhere near peak torque until 5000 rpm, it really isn't all that unreasonable for the trans to shift at 3000.

 

If you are concerned about engine wear, don't be. These engines like to rev and 3k is nothing for them.

 

If you are worried about fuel, again, don't be. Fuel use is more about throttle opening than it is about RPM.

 

If you are running 3k rpm at a very small throttle opening, you are using less fuel than if you ran at 2k with your foot stomped on the gas to make enough power to lug the car around at low RPMs.

[nipper]

Isnt it cold down there, or close to it?

 

The tranmission wil hold gears untill it warms up. Also you can manually shift the car. Have you checked the tranny fluid level?

 

There isnt a hell of a lot that can be done as it is puter controlled. Say, disconnect the battery for 30 minutes and let the memories clear, see if that helps.

 

 

nipper

[howpow]

Hi Gloyale. Yes I am aware that it is only a 2.5lt four, and if I had my foot pressing the pedal a reasonable amount I wouldn't mind the revs, but when moving off slowly in traffic I don't expect to still be in second at 33 MPH. I'm not worried about the fuel or revs, I take it up to the red line every now and then. If driven manually in Sport mode and watching the up and down arrows it allows you to change at 1800rpm and around town on level ground is very happy at those revs. Maximum torque may be at 4400 rpm but the engine is known for a wide torque range and pulls quite happily down low.

 

Hello Nipper. It's not too cold in Melbourne, temperature ranges from about 32F to 110F. I will check the fluid level and try resetting it as you suggest. Thanks for your input. I also have a 1976 GF Hardtop and a 1987 XT Turbo so I am a Subaru fan.

[eulogious]

I believe the trans you have is a phase II 4EAT (someone correct me if I am wrong on this) so the TCU and the ECU communicate a lot more than the phase I 4EAT, which makes it more difficult to do anything to the TCU. I for one have modded a phase I tcu to run some custom firmware, and because of that I can change all my shift points to whatever I wanted to. Granted the transmissions are slightly different, they are basically the same trans using the same rom code on the TCU. So knowing what is involved with actually changing the shift maps, I would say that the dealer will not be able to do anything for you. The only true way that you will be able to modify the shift maps is by modifying the TCU to accept some sort of new firmware. This is assuming the phase II TCU are similar to the phase I, but I believe they are very similar though. Also the way the TCU is designed, you can not change it. The firmware is stored on ROM (Read only memory) so by design you can not change it once it's been written to. So once the factory writes the ROM onto the chip, you can not change that ROM without physically modifying the TCU itself, which is what I did. So unless the dealer has some sort of special ROMs sitting around running some sort of custom subaru TCU code with custom shift points, and is willing to desolder and solder on a new chip in place of the old one, the dealer can't really do anything for you. Of course they might offer a "sport" version of the TCU (I have no idea, just talking out my arse here) that you might be able to just plug in, but of course that will cost you $750 or more for that bad boy, considering a new TCU is almost $600 :-\

 

I was able to modify the TCU myself and add the custom firmware, but it took me a couple months of research and lots of help from some board members here. I did not pioneer it, I just copied what someone else did. Here's my build thread:

 

http://www.ultimatesubaru.org/forum/showthread.php?t=110222

 

Granted I did more than just change the shift maps, but you have to basically do all of in order to run the custom firmware needed to change the shift maps.

 

There are a couple of sites that explain the process in great detail. This site:

 

http://www.alcyone.org.uk/ssm/tcuinfo.html

 

Deals with the svx, but it uses the same processor as the legacys, and has a lot of info on what is actually required to change the shift maps. It's really intense. There's a lot of variables that go into the shift calculations, and LOTS of shift maps for the TCU to choose from, so it's not just a "simple" procedure to change the shift points. In fact, I need to change my shift points from 1-2. I have really hard shifts right now and I could change the line pressure which would fix my problem, but it's so intense to try to actually figure out what to change in the ROM itself that I just haven't change it it, and probably wont. And I am already running the modified firmware Presslab on the other hand did change the shift maps, and his are the ones that I am using at the moment. So it's possible, but it's a PITA that I really don't care to deal with myself.

 

Now there's another site that will actually do some of the modding themselves, so you might want to check them out, but it's not cheap. Again, they are dealing with the svx, but it's really the same ROM code.

 

http://www.ecutune.com/

 

Then if you really want to go crazy, there is another site that will actually modify parts of the trans itself to shift better and all that jazz. They are not cheap, but the work that they do is suppose to be good.

 

http://www.importperformancetrans.com/subaruauto.shtml

 

Hope that explains some of it for you, and why the dealer probably wont be willing to help you out! Again all my info is based off the phase I trans, but it should apply to you. Good luck!

[eulogious]

I should also mention that here in the US, we did not get a "power" button to enable the trans to go into "power shift" mode. "Power" mode makes the shifts more aggressive and things like that. So in the US, we didn't get the button, but the JDM cars did, so the svx guys found out by grounding a pin off the TCU, you can enable the TCU to go into "power" mode all the time. That might solve some of your problems. Just throwing that out there.

[howpow]

Thanks eulogious. I'm convinced, unfortunately although I am mechanically capable I'm afraid electronics are beyond me. I guess I'll just have to learn to live with it. Thanks for your very detailed reply, I appreciate the amount of time you have spent. I did check the fluid level which was a bit low and topped it up which seems to have made a slight difference but I'll have to give it a good run tomorrow to see.

I've printed your amazing post out so if I meet an electronics whizz in my travels I'll have the info.

Thanks again.

Howard

Edited April 24, 2010 by howpow

[eulogious]

I am glad that I could help explain it for ya. Can't remember if it was mentioned or not, but try changing the fluid, maybe try a different brand? Synthetic maybe? I know that the 4EAT is sensitive to low fluid, and the fluid itself, so it might help.

 

You could just add the paddle shifters and then have complete control over when it shifts I kid You could also just use a combination of the power button and manual button and have "sportier" and more controlled shifts. Just a thought.

 

Hope that it just works it's self out, good luck!

[Flowmastered87GL]

funny... when I read the thread title I figured you wanted to make the shift points higher.

 

Thats why I bought a 5 speed... I can shift when I want