Originally Posted by Gasmiser
Would a 66RFE play nice with a PCM on a 2012 1500 5.7l? I am looking into a engine/tranny swap for my 2006 Mega Cab, because I want add the MDS and vvt. So, I am wondering if the move to a 66RFE would be possible, or would i run into the same pre-'12 PCM issue you mentioned above.
While the solenoid module would not need to be changed, the other considerations still hold true. I'm not sure offhand whether the converter would be identical or not (probably is, but I'm not sure).
But the biggest issue would be the PCM. The gear ratios for the 66RFE are different from the 65RFE, so if you just hook it up as is, you will blow gear ratio error faults immediately (and continually). It would be unusable for that reason. And I don't know of any way to get the PCM reprogrammed to the new ratios.