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I recently did a new tune to my 2005 5.9 Auto and for the first 50-60 miles, the truck would refuse to down shift to 3rd when accelerating up hill with 90% or more throttle position. After about 60 miles the truck began to downshift when accelerating uphill at more than 90% throttle. Do these trucks have a built in learning feature for down shift or did I just have some random anomaly? Unfortunately, my laptop died and i wasn't scanning during this time.
Yes the 48RE has shift lag times it has to relearn after an ecm flash. If you?ve messed the shift tables without making the necessary modifications needed in hidden parameters it?ll throw things off more and you won?t be able to get to follow precisely what you want either and will have limited adjustablility.
Thank you.
Jim P , how do we access hidden parameters? I’ve tried to do some tuning on my trans and it doesn’t help much . I hate the lock up at 50 mph and would like to make the 1-2 shift hang out a little longer.
You need to purchase user defined parameters, learn hexadecimal, learn how to create user defined parameter files and know what to look for or how to find what you are looking for to get the hidden parameters.
I have no idea what any of that means ! Lol
Haha! Let?s just say it?s not as simple as clicking a button lol. It took me and one other guy months to figure it all out and each of us months afterwards to develop the shift and lockup schedules we each use and the modifications we use in hidden parameters.
99.99% will still call BS on tuning a 48RE and say it just can?t be done and to an extent, they are right but, only if they don?t make the necessary changes to hidden parameters required. Without the changes you got very limited amount of what you can do as far as tuning the 48RE.
The hidden parameters make all the difference, the transmission is actually quite tuneable once they are modified.Quote:
Originally Posted by Jim P
I understand hexadecimal, but I lack the knowledge and tools to pull a binary file, and wouldn't really know how to find the hidden parameters myself if I had a bin file to look at. Then, to turn it all into an editable parameter with HP Tuners, I got nothin'.
So, I had Jim modify the hidden parameters in my tune file for me, and I couldn't be happier with the results. The tables that are open to everyone actually work quite well once the hidden background stuff is ironed out.