Originally Posted by TransEngineer
I should also note that 66RFE transmissions use an extension (or 4x4 adapter) that are not compatible with 1500 models. So those would have to be swapped out (which can be done, the parts will interchange). But changing the extension/adapter may also change the rear geartrain end play, and if the end play winds up out of spec, it would be necessary to tear the trans down and change a selective spacer to adjust it.
I should also note that the solenoid module used in the 2012 (66RFE) transmissions is NOT backwards-compatible with 2010 and earlier model years, so you'd also have to swap out the solenoid pack.
Also, the torque converter now being used with the 66RFE is different from that used in 2011 and prior years. This is not a big deal (the new one would probably work fine), but for anyone trying to keep emissions legal (not likely a huge concern for anyone undertaking this!), the new converter could change the emissions performance.
So I guess things are never as simple as they seem at first. Sorry.....
I saw these transmissions side by side a while back. The converters are interchangable and the housing is exactly the same. Don't know about the 4x4 but my 2x2 is the same. I didn't get to see the harness or any wiring though. As far as emissions I don't see what that has to do with it but I repspect your findings. I don't think anyone would care about that if they plan on using a stall speed converter down the road anyway. Say in my case, (2009 RCSB Hemi ST) why can't I swap out the entire engine control system (pcm/tcm, it's all in one housing) from a 2012 HD 2500 Hemi ST....the same model except it would be RCLB? I even thought of taking the pcm appart and sperating the tcm. The 68rfe is supposed to be two separate units but it's been a while so I may be wrong. Plz don't give up looking into thisd....you started this now you have to finish. You are the first person I saw that has had any interest in rthis and you're a trans tech...help us!