algol Posted April 9 Share Posted April 9 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. Link to comment Share on other sites More sharing options...
silverton Posted April 10 Share Posted April 10 Without someone being able to reflash the TCM you're kinda stuck with what you have. It may even be an adjustment the driver must make for the car, instead of WOT... try like... 90%. Link to comment Share on other sites More sharing options...
algol Posted April 11 Author Share Posted April 11 We downloaded FreeSSM and managed to reset the TCU. The trans seems to be fixed now! Link to comment Share on other sites More sharing options...
algol Posted April 12 Author Share Posted April 12 Well for unknown reasons it started hitting the limiter again today. Any ideas welcome! Link to comment Share on other sites More sharing options...
silverton Posted April 12 Share Posted April 12 Resetting the TCM puts it back to default values. It's receiving inputs from the ECM it's not expecting so it starts to adjust for those funny inputs and now here we are. Are you tuned? Link to comment Share on other sites More sharing options...
algol Posted April 12 Author Share Posted April 12 Yes, I'm tuned. Link to comment Share on other sites More sharing options...
algol Posted April 12 Author Share Posted April 12 8 hours ago, silverton said: Resetting the TCM puts it back to default values. It's receiving inputs from the ECM it's not expecting so it starts to adjust for those funny inputs and now here we are. Are you tuned? On 4/10/2024 at 8:12 AM, silverton said: Without someone being able to reflash the TCM you're kinda stuck with what you have. It may even be an adjustment the driver must make for the car, instead of WOT... try like... 90%. Do you know how to reflash the TCM? Link to comment Share on other sites More sharing options...
silverton Posted April 13 Share Posted April 13 AFAIK, the TCM is not flashable. You may want to look into an upgraded valve body if available it may help. Your tuned ECM is giving the untuned TCM inputs it's not expecting and is doing its best to make it work. An unfortunate byproduct of tuning and upgrading an automatic, if you google you'll find it's not just you. If you put your car back on a stock tune does the transmission behave normally? If it still acts up then it's not the tune and you have another issue. I turbocharged my 2001 GC-RS with an auto. If I wanted to drive it spiritedly I had to shift manually, otherwise it was already in third/"fourth" gear by the time we were across a normal sized intersection, acted like a CVT. Link to comment Share on other sites More sharing options...
algol Posted April 13 Author Share Posted April 13 2 hours ago, silverton said: AFAIK, the TCM is not flashable. You may want to look into an upgraded valve body if available it may help. Your tuned ECM is giving the untuned TCM inputs it's not expecting and is doing its best to make it work. An unfortunate byproduct of tuning and upgrading an automatic, if you google you'll find it's not just you. If you put your car back on a stock tune does the transmission behave normally? If it still acts up then it's not the tune and you have another issue. I turbocharged my 2001 GC-RS with an auto. If I wanted to drive it spiritedly I had to shift manually, otherwise it was already in third/"fourth" gear by the time we were across a normal sized intersection, acted like a CVT. 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. Link to comment Share on other sites More sharing options...
silverton Posted April 14 Share Posted April 14 6 hours ago, algol said: 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. You may want to pop into a dealer and see if your TCM has any updates available. When I got my 3.6R i thought it was very boring, but an ECM/VDC update woke it up and it's a blast to drive now. Link to comment Share on other sites More sharing options...
algol Posted April 14 Author Share Posted April 14 22 hours ago, silverton said: You may want to pop into a dealer and see if your TCM has any updates available. When I got my 3.6R i thought it was very boring, but an ECM/VDC update woke it up and it's a blast to drive now. 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. Link to comment Share on other sites More sharing options...
silverton Posted April 15 Share Posted April 15 15 hours ago, algol said: 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. Most wouldn't think to look for a TCM update unless it was a line item on the RO. It's a long shot since the car is getting up there in age but worth a try. Link to comment Share on other sites More sharing options...
algol Posted April 22 Author Share Posted April 22 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! Link to comment Share on other sites More sharing options...
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