545rfe ?s

I have a TCM out of a 2002 Jeep Grand Cherokee in the shed and it will give the 45RFE the extra gear (545RFE). They are the same trans and yes I did test this. At the time I used it in my 2002 Dakota with the 4.7. I don't see any reason you couldn't use the 2003 Ram controller or the jeep controller to stand alone control the transmission as long as you give it the appropriate inputs. If using a G3 Hemi with it, then just get a hotwire harness setup to run an 05 PCM. The 05 has some trans tuning functionality the 04 does not support. 03 used a dual setup that had one for the engine and one for the transmission. There is probably a way to make that operate regardless of which engine is in front of it.

In all honesty, unless the engine is stock I would stay away from the 545 or have it built to handle more. Several guys have put 6.1's in front of them only to kill the trans pretty quick. So if at any point you want to go to a performance build you may want to investigate this.