i3 used for 2.82 to 3.06 gear swap issue

[Andrew Higdon]

Hey there Mike. I did speak with you on the phone several weeks ago and you were very helpful and seemed to have fixed my brand new i3 tuner, which I needed to tell my ECU/TCU about the new 3.06 gear ratio I swapped into my 2006 Dodge Magnum RT. I have never agd a single hiccup with this transmission in 208,000 miles, and I don’t think I do now, but I want to keep it that way. After programming the gear ratio to the ECU using the i3, it seemed to work. But here is the symptom and I’ll tell you what I did . The symptom is that with what the computer calls engine overspeed, I call excessive wheel spin, which was kinda the intention at that moment. But the car jumps out of gear and I guess into neutral. I put it in neutral every time, restart the car, and from a slow roll everything comes back like nothing ever happened. What programming changes can I perform to prevent this. Here’s some important info. I swapped an entire 2011 Charger Pursuit rear subframe assembly under my 2006 Magnum RT. Went like butter, except for one thing. The wheel speed sensors for the 2011 car won’t fit the connector at the body of my 2005 car. The entire subframe is from the 2011 Charger Pursuit, except I swapped over the nicer and newer suspension parts from my car onto the 2011 cradle. So the hubs. Axles. Etc, are still original to the Pursuit. But all of that looked amazingly fresh, and I got this from a car at LKQ and it all looks good. When fhe 2011 wheel speed sensor connectors wouldn’t fit my cars harness, I just put my 2006 (but relatively new) ones in their place and they fit perfectly. I read that the 2011 uses active sensors and wouldn’t work with my sensors or computer. Too bad my car reads them fine. But at first, my car was throwing codes like incorrect 4th gear ratio, which was the only one that concerned me. The rest were network codes that were likely thrown while swapping it all out. Of course I disconnected the battery and all of that. Well, as far as driveabilty, it was initially great and then would start slipping badly, and freaks me out a bit. I rechecked the program, reset to factory tune, then back to the i3 Diablo Tune with 93 octane which I already run. I’m pretty sure I removed the agressive trans shifts option, as well as the high rpm limiter back to like 5500 I think. Basically the canned Diablo 93 tune without too many other aggressive settings. But obviously programmed in the 3.06 gear. I used an Autel OBD scanner to keep track of real time data. Sure enough, each speed sensor was reading accurately and driving straight resulted in very consistent wheel speeds all around, and correctly reflected during turns and such. Everything seemed great, and I was happy to defy the naysayers who said the 2011 rear cradle wouldn’t bolt in. WRONG!
And that my compiutet and passive sensors wouldn’t be able to read the 2011 tone rings. I bench tested both the 2011 sensors and my 2006 sensors and I could not find any difference in function or impedance. Indeed. Everything seemed and seemss to working as it should. But that first shakedown run, I stopped on an empty long straight stretch for a 0-60 test. Truly though the road was dry enough to not spin much at all. I preload/power braked to about 1500rpms, and let her rip. Well, the back wheels cut loose so strongly that the car moved about 1 foot and sat there spinning both back wheels, rpms shot up but are limited I thought, but the onto went to about 5100rpms. The newfound power was astonishing. The tires are fresh and it wouldn’t do the even of the road was wet, not like that. Well, it jumped out of gear. I guess they call that limp mode. So I rolled to the side and restarted the car and all was good, like nothing ever happened. It has done the same thing about three times. Is there a setting I can change to keep this from happening. That NAG1 has never done that before, ever, even with 208,000 miles. One of the codes thrown when that happens is aomething like. Engine over speed. Never seen that code before. I clear the codes and the thing runs like a monster, and what’s most impressive is the 1-2 upshift. It’s unreal. But how can I keep it from freaking out. I have not had one rear wheel speed sensor code. It seemed like a couple of drive cycles is what is needed for adaptations to learn. Any chance you could write a new tune to address the over speed and the response ? Maybe an RPM limit when sensors show huge wheelspin numbers. You were great help a few weeks ago.
Cheers

[mikel]

the issue here is hitting the internal tcm rev limiter.
post the info file from your i3 please and we'll check the tcm cal and see if we can bump it up for you.
if you are using the i3 to enable the raised shift points, setting them back to stock value should resolve it as well.
A Mopar TCM is also a good option here.