45 RFE Transmission complete failure

[mauleguy]

Hello All, I have owned this truck since new. 2006 Dodge Ram Heavy Duty 2500 Hemi 5.7 with Automatic Transmission. The first year I owned it I had it back to the dealership twice for Tranny problems but since then it has been flawless. I have 145K miles now. I was on the freeway doing 70 when I put my foot in it to pass, it downshifted and then nothing. Transmission just stopped working, no loud noise etc. Coasted to a stop and had it towed home. The fluid level checks correct. It does not move when shifted into any gear. It does sound slightly different then it did I believe with a very faint wine sound but if you had never heard the truck before you probably would not notice the sound. I dropped the pan and there is no metal in pan, fluid in pan was clean and smelled normal. Here is my question: Could this be something simple like a solenoid etc. or am I looking at something more mechanical like a input shaft etc. Any help would be appreciated

Thank you,

Greg Miller

 

[crazykid1994]

First things first any CEL or hook up a scanner to see if any codes? Could have lost line pressure. May want to hook a gauge to it to test pressure. If that’s the case there are quite a few things to check. I would also start with making sure the filters and everything are good. If the filter came loose you’ll lose line pressure. Any bad gaskets you lose pressure. Maybe the shift plate gasket leaking. Mind you I’m just tossing out guesses on where I would start and I’m only a home mechanic so I’ve got no clue.

 

[mauleguy]

Yes just checked and I have 3 codes: P0700, P0715, P0720

P0700 is set when the PCM detects a malfunction in the transmission control system. This malfunction causes the vehicle to set a Check Engine Light and trigger a failsafe mode. Once the failsafe mode is set it will remain until the fault is repaired or normal operation is detected.

P0715 is triggered when the Engine Control Module (ECM) or Transmission Control Module (TCM) detects an irregular signal coming from the input/turbine speed sensor in the transmission. ... It is usually a three-wire sensor that reads a reluctor ring in the transmission

The P0720 code is a standard OBD-II trouble code that detects an issue with the output speed sensor circuit. The powertrain control module (PCM) relies on a signal from the output speed sensor, so that it can determine the correct shift strategy and send that information to the transmission.

 

[Recoil]

Out of those 3 codes, I'd be looking at the speed sensor.

 

[mauleguy]

Thanks, I got them ordered

 

[mauleguy]

I was told just now by a Transmission teacher at a college that I would have reverse even if the sensors were bad. He says that reverse does not work through the electronics , it's operated by the manual valve that's moved by the shift linkage, so if the transmission was mechanically okay and things are totally unplugged you should still have P,R,N and limp in via manual valve. Anyone know if this is true

But he did say he would have to look up my application to know for sure.