2001 Dodge Ram 2500 Diesel I have a transmission that is downshifting at 60 mph and above to third gear. Which causes an over revving of the engine that gear, which in turn the transmission will no longer provide forward motion power. I have replaced the throttle position sensor, cleaned all the ground wire connection points I can find and rebuilt the alternator. I was told I might have an RF problem in the wiring because the voltage fluctuates when I depress the accelerator pedal. Is there a fix for this or is there some other problem?

 

Any codes? Trans Temp lite come on? had any work done to the trans lately?

Voltage should go smoothly from less than 1 volt, to greater than 3.5 volts as you lean into the accelerator. Best to test with an analog meter, as the digital gauges bounce around anyway. If you aren't getting that, replace the TPS. (again....)

 

No codes. No trans light. No work done. Other than fluid change 1 year ago. We used a MOOG computer hooked to the truck port. Watched voltage jump while driving and while sitting still. Just moving the accelerator pedal. Shut off engine with key on and no fluctuation in voltage with engine not running while moving pedal..

 

Is there a in line (Electrical) filter that can be installed to get rid of the RF disturbance. I think the disturbance is causing the computer to shift when it shouldn't.

 

You might wanna go thru and check all of your grounds (battery, frame and body), especially those body grounds.