as you all may know,I'm doing a 4.7 to 5.7 Hemi swap in my 2001,Dakota Quad Cab.The 4.7 had a 45 rfe "4 spd" tranny.. I replaced that with the 545rfe that's on the Hemi...My first question is. Can I have my tcm re-programmed to give the 545rfe the extra gear,or do I have to change the tcm..
My second question is... My wiring harness on the 2003 Hemi Motor and 545rfe, is still hooked up to all the sensors plugs etc....But the harness is cut just above the motor leading to the computers. ecm/tcm..DO I STILL have to buy the complete harness ?OR can I just cut the new one from the doner truck and splice them in...
QUESTION #3==When I bought my doner motor and tranny,The man I bought it from said he "THINKS" the motor and tranny is a 2003...I don't know..How can I tell...I don't want to buy a 2003 wiring harness and the motor ands up being a 2004-or-05..It won't work...ANY help on this subject will be appreciated..

 

Yea you have to have the TCM from the 545rfe... Did you not have the part? I also would never splice into electrical parts leading to the ECM/PCU or computer.

Good Luck!

 

Physically, the 45RFE and 545RFE are the same transmission, it's the TCM's programming that's different. It should be fine, but you will not have the "fifth gear." Once you get it flashed all should be well.

 

This should be in a tech forum, not brand news. I will request that it be moved to the proper forum.