No reflash is needed to operate the 545rfe trans if using the factory computer (05 and up). 03-04 computers (ecm and tcm) are the bastards, so use an 05 and up, way more tuning and adjustments. ................
You are partly correct.....the 2003 Rams have separate ECM & TMC's the 2004 Rams, which is what I have, has a combined ECM/TCM. The 05+ ECM is a better choice as it has trans tuning support.