I need some help cause I am at my wits end with this problem...

I have a 2002 4X4 Dakota crew cab automatic with a 4.7L, it has about 160,000 miles

The problem im having is a multi-part issue...first the ABS and Parking light are always on, my the speedometer works about 90% of the time and when it does work it works at all speeds.

Second, starting about a week ago it started running at high RPM's it idles correctly but when I am driving the engine is always reved up, when it shifts it only drops about 300 rpm, when I say high RPM i mean it is never below 1700 and every gear hangs around 2000 wether i give it gas or not and the transmission will not shift unless I let completely let off the throttle.

The transmission fluid and filters are about 8500 miles old and it has new oil and coolant, I have changed the speed sensor on the rear diff and the two on the side of the transmission that look the same as the one on the diff with no results, it has a new TPS and the throttle body and intake are clean. I have also reset the PCM. I have another sensor called the "Output shaft speed sensor" that is plastic and is supposed to thread into the transmission but for the life of me I cant find where it is located to change it out.

My gas mileage has gone to complete **** and I want this figured out so any help I can get will be greatly appreciated.

Thanks, Matt

 

I will move this to the 2nd generation Dakota sub-forum.

 

out put speed sensor is one of those you changed on the side of the transmission. check to see if there is corrosion on the connector and if you have voltage to the sensor. also check your map sensor if it has one or vacum leaks

 

For the high idle I would guess a vacuum leak. Check the hose that attaches to the back of the intake manifold. That hose became disconnected and caused a high idle just like you described.

 

I would say the speed sensor, had the same problem, When i changed it the problem went away and ran smooth again.

 

Do you have any codes?

Key on, off, on, off, then leave on. It'll display in the odometer window.

 

The 300 RPM drop between shifts sounds like the trans is slipping and/or convertor is not locking up.

This happened to me. The lockup clutch came apart, gave me a lockup failure code, then an OD failure code, then I lost OD, then I lost third, Then I lost second right when I got home. The clutch material had clogged every sensor and solenoid in the trans. The only reason my speedo works is that it reads off the axle, not transmission, else I would have lost that too. I barely had first gear to get it on the lift.