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You were right that the tuning was confusing the TCU. We reset the DBW tables and the TCU memory. It’s now working. Hopefully that continues!

Thanks for that idea. The dealer replaced the valve body 5 years ago. So, I kind of doubt anything new is out. But I need to go to the dealer to get a part anyway, so I'll inquire.

Yea, manual mode works much better and is quite fun. Shifts are very firm and quick if you don't count the computer being slow to start the shift. But I know that some people don't have these issues with automatic mode, even though they are running more power.

Do you know how to reflash the TCM?

Yes, I'm tuned.

Well for unknown reasons it started hitting the limiter again today. Any ideas welcome!

We downloaded FreeSSM and managed to reset the TCU. The trans seems to be fixed now!

I have a 2005 Legacy GT 5EAT. The car is running a VF52 turbo, new fueling, down-pipe, and up-pipe. The transmission has been rebuilt by IPT. The only issue I have with the car is that the TCU doesn't seem to know when to shift in automatic mode. It tries to shift 1st and 2nd gear too late so that it hits the limiter under WOT. The car shifts nicely in manual mode. There is no mechanical issue anyone can recognize. It's just the computer doesn't seem to know when to shift the car given the big HP increase over stock. Any advice is welcome. I don't know how to change the shift points. I know though that there are others with 5EATs running even more HP.

I drove around and did some testing today. Under full throttle in manual mode it shifts pretty well. I got one shift from 1st to 2nd in about 1000rpm under full throttle after hitting the button. The shift felt good. Sometimes it takes a little longer but it's totally manageable. But auto mode gets confused. It revs too much in 1st gear. It will hit the limiter under full throttle and then shift. As I know it can shift (when I am in manual mode), it seems the problem has to do with the programming not the hardware. I looked at my records. The valve body was replaced by the dealership in 2021.

Well the issue isn't that the shifts are hard. They didn't use to be hard. The shift kit though has made them hard when on throttle. When driving normally it's just like it was basically. But that's what it's supposed to do. The whole idea is to have firm sporty shifts. So, now when under full throttle it shifts hard into 2nd and the car kind of lurches forward. It's a very sporty shift. The issue is just that first gear shifts slow, not that it shifts hard. It also will hit the limiter in auto mode. Both problems are not the end of the world and totally manageable, as I can just use manual. I use manual mode anyway if I'm having fun with the car. But if possible I'd like it to be better. Not going to spend a million hours on it though.

It sounds like you think the issue might just be an old version of the transmission software never updated. Is that right? A friend of mine thinks it could be a faulty solenoid.

Thanks. This is good information.

Okay thanks for the info. Would any trans shop be able to access the TCM?

LOL! It's not my job to educate you on how to be a polite member of society. That was for your parents, but I guess it's probably too late now. I had always assumed that the slow shifting was just a limitation of the automatic. I had read how the TCU is slow. I just accepted that it was slow to shift 1st to 2nd and that this was made worse by the HP increase. As I could just time it and hit the button early, I never worried about it. My dad took it to subaru when I was overseas. They flashed it and replaced a solenoid. When I got it back years later it was shifting fine in auto, but in manual 1st was still slow to shift. I again assumed this was just a limitation of the transmission. I decided to replace the turbo, as it was underperforming anyway. I told the shop about the transmission shifting slow, but they said we should see how it behaved after the mods before messing with it. That seemed reasonable I guess. When I got the car back the transmission was not shifting correctly (very slow to shift in 1st and 2nd). No one knew what to do but to try the shift kit, which was a total improvement. However, 1st gear remains slower than I'd like and hits the limiter in auto mode under full throttle (just doesn't shift in time). I can take it to a transmission shop and have them look at it, but I guess I'm hesitant to think there is gonna be an easy solution. I just wanted to get some feedback and ideas so I knew what to talk about with the trans shop. Anyway, there is no need to be rude to me just because I may not have made the best decisions. I admitted upfront that I am no expert and learning as I go.

There is no need to be rude. The issues I had originally I assumed were just limitations of the auto. There was also no dealership in my town. So dealing with issues was a pain. I lived overseas for a while and during that time my dad had the car. He did end up taking the car to the dealer. They replaced a faulty solonoid and reverted the car to a stock tune (even though he told them not to flash it). The car was shifting fine in auto mode when I got it back from my dad. Did not hit limiter. In manual mode it still took 1500rpm. But it has always done that. I brought up the shifting to my shop but they said we should worry about that later. After the mods the trans behaved erratically. I took the car back to have a shift kit installed. That has basically solved the problem. It’s just first gear now that is slow. The trans is certainly not failing. And the shift kit was a good mod and necessary as far as I can tell.