Ram 47RE TC searching


Staff member
Dec 14, 2002
New Jersey
About the only questionable thing about my Ram is that the AT sometimes gets confused at around 45-60 mph with light throttle.

The AT was replaced about 10k miles ago. No other records of prior AT replacement.

I liked the idea @ram_man had to post a video of shifting behavior.

This is one of the behaviors:

The other being that sometimes instead of just unlocking and re-locking the TC, it will fully downshift and then upshift again.

Fluid looks great and level is fine. Transmission shifts well otherwise, and this is sporadic. It seems to be more likely on flat land, when the truck is cold.

I suspect it is the TPS on the injection pump. I’d kind of like to install a TC lockup switch, and I suspect it may help with this too.

Any thoughts?

Here’s more normal operation:

Truck was lightly loaded. Had maybe 1500 lbs payload in it. Was not accelerating hard.

*Check the Throttle Position Sensor (TPS) voltage, when the problem occurs, for a erratic change in voltage.
*Check the Park/Neutral switch (P/N). It should not read park or neutral when in drive.
*Check Throttle Position Sensor (TPS) voltage with the throttle closed. It should be 1.0 volts. Monitor the brake switch input to the PCM for a brake applied signal when it is not applied.
*Check the Transmission Temp Sensor for erratic readings.
*A/C Ripple out of the Alternator can cause some strange things.

When driving it & the symptoms appear......Take your left foot & apply pressure to the underside of the brake pedal, If the symptoms disappear....You have a brake switch/brake pedal issue.
Thanks. I’ll need to look into the FSM for doing those tests. Not sure I can check tps voltage when it happens, as it’s around 50 mph.
I use a scan tool, Though the engine is purely mechanical.....OBD2 protocols still apply to the TCM, Which on your Dodge is just a Gas PCM with the gas engine controls removed.
Ok thanks. Haven’t looked into if there’s an obd port or anything in there. I think 96 was the first year it was mandated, but not sure if diesels were exempted.
I believe this vintage of Dodge Ram Cummins had a known issue regarding voltage from the alternator causing sporadic issues with transmission tc function.