Rear Diff gear change now TCM reverts to stock settings.

[KennyLives]

2014 Challenger R/T 5.7l w/5A Nag1. We swapped the rear gears from 3.06 to 3.91, made the gear ratio change using the VCM Scanner, after that found that all the changes we made to the TCM are reverted back to stock settings, even if we flash the TCM again with our changes it doesn't stick. Is this expected behavior or did we miss some changes?

Thanks,
-Kenny

[06300CSRT8]

Was the TCM in the vehicle the stock one or a replacement/aftermarket one?

[KennyLives]

Sorry its the stock TCM that was tuned with HP Tuners when they first supported the ability. I have tried apply the tune several times. The only thing I haven't tried is reverting back to the 3.06 ratio (with out starting or driving the car) and see if I can apply TCM changes back to see if they stick. This is boggling as everything I have read changing the gear ratio hasn't messed with other peoples TCM changes.

Thanks for any and all help.
-Kenny

[KennyLives]

After some trial and error figured out its one of the settings causing this, I'm going thru each setting to try and figure which one it is. Not totally resolved but at least I know the cause just need to narrow it down to find out which it is.

-Kenny

[06300CSRT8]

Did you pinpoint the change that caused this?

[Pector55]

After some trial and error figured out its one of the settings causing this, I'm going thru each setting to try and figure which one it is. Not totally resolved but at least I know the cause just need to narrow it down to find out which it is.

-Kenny

I just upgraded from 3.06 to 3.91's as well. I did the gear change and kept the default tire size. I then did the init. What else do I need to change?