Hello, new here so bare with me on this one. Did a hemi swap with a 2005 1500 5.7, 545rfe trans to my classic truck. Used the stock wiring harness and ECM. Motor runs awesome but the trans is stuck in limp mode. The ECM is not seeing the trans for some reason. The sensors such as temp and pressure show up on the scanner but have no values. I can disconnect them and do not get any fail codes. I tried a replacement ECM and same problem. Anybody have any ideas to try on this.

Thanks

 

Are the sensors getting their power feed?

 

Yes, 5.3 volts.

 

Does the ECM need to see the wheel speed sensors?

 

A friend who works in the plant told me they are notorious for changing the wiring. I found this to be true when I swapped worn cloth for a nice set of leather seats. The wiring was different so even when I pugged the original to the truck wiring harness the wires connected to the seats were different. The only thing that was the same was the seat belt light. Just food for thought.