Originally Posted by garner
Can you go further into detail about this? Is there a different tune in the 2012s than the 2011s cause of the new transmission tuning?
No, I'm not talking about trans shift pattern or tuning. I'm talking about the actual, physical torque converter. The 2012 converter is a new design, and the internal blading inside the converter is different. Therefore, the 2012 converters have different stall torque ratios and K-factors (characteristic curves) than the 2011 converters. Since the converter performance (output torque, efficiency, etc.) is slightly different, we can't just bolt a 2012 converter into a 2011 truck. EPA would view this as a change in the emission and fuel economy characteristics, so we would have to re-certify the 2011 vehicle (with the 2012 converter) to verify that it still meets emission regulations.