Attention: TDR Forum Junkies 
Hey all, I'm posting this hoping it will help any others with what seems to be a common pain in the neck for anyone owning a 2003-'04 dodge ram diesel with 48re transmissions.
So here's what happened to my truck. One day leaving the house it felt very sluggish going down the street (stuck in "limp mode" I learned) and would only shift up 1 gear and down 1 gear or go into overdrive. I then noticed on the dash that the overdrive light, cruise control light and the gear select indicators were not working. This led me to believe that it isn't a mechanical trans issue but an electrical either within the harness or the PCM itself. So I borrowed a friends Autel universal scan tool and was not able to read any transmission functions (trans temperature, governor pressure solenoid etc.) from the TCM, but the TCM was getting 12 volts along with all the other PCM info for the engine and everything else.
I started by disconnecting both batteries and all three harness connectors from the PCM mounted on the firewall (pass. side), then took the lowest connector housing totally apart and noticed two pins green with corrosion and about to break in half. I then went to my local junk yard, cut a pcm harness connector from a donor truck for the correct connecting pins, went back home to splice and solder the two replacement wires with there pins, reassembled the connector housing and reconnected both batteries. BOOM BABY! IT'S FIXED!!! problem solved!
Thanks for reading and I hope this saves lots of you out there some time and money. - Skull
So here's what happened to my truck. One day leaving the house it felt very sluggish going down the street (stuck in "limp mode" I learned) and would only shift up 1 gear and down 1 gear or go into overdrive. I then noticed on the dash that the overdrive light, cruise control light and the gear select indicators were not working. This led me to believe that it isn't a mechanical trans issue but an electrical either within the harness or the PCM itself. So I borrowed a friends Autel universal scan tool and was not able to read any transmission functions (trans temperature, governor pressure solenoid etc.) from the TCM, but the TCM was getting 12 volts along with all the other PCM info for the engine and everything else.
I started by disconnecting both batteries and all three harness connectors from the PCM mounted on the firewall (pass. side), then took the lowest connector housing totally apart and noticed two pins green with corrosion and about to break in half. I then went to my local junk yard, cut a pcm harness connector from a donor truck for the correct connecting pins, went back home to splice and solder the two replacement wires with there pins, reassembled the connector housing and reconnected both batteries. BOOM BABY! IT'S FIXED!!! problem solved!
Thanks for reading and I hope this saves lots of you out there some time and money. - Skull
