I was told this is the place to come for Dakota answers.
I just bought my first truck. When I test drove the truck every thing seemed normal to me as far as the speed to RPM but a friend of mine said that he thinks the transmission is not shifting into Over Drive. I didnt think anything of it till yesterday I was on the highway and for one second the the RPM droped from 3500 to 2200 then back to 3500. I was traveling at 73 mph. Am i crazy or is there a problem?

 

Sounds like you do have a problem. Tons of possibles. Wires to the speed sensor to the OD solenoid. Do you have a check engine light?

 

Welcome to DodgeForum!

To add to Crazy4x4RT's list, it could be a temperature related problem. Does your truck run at normal operating temperature? The computer won't let the transmission shift into overdrive until it is in its closed loop.

 

Very quick replies.
No check engine light. I push the OD button to the left of the steering wheel and the light goes on and off.
As for the temp the gage never goes over the first bar from the "C". I was going to do a coolant flush as the coolant in there looks to be as old as the truck.

 

Chances are if the gauge never gets up, the engine is running too cold and staying in open loop. Run the codes (even if the light is not on) and see if you get a code 17, which is closed loop temp not reached. If 17 comes up, I'm going to guess you need a coolant flush and a new thermostat and that might fix your OD problems.

 

Probaby wouldn't hurt to service that auto tranny either. Check/change the fluid and filter.

 

my bet is the OD solenoid. Had this with my 90 many yaers ago that was it...

 

Looks like i have my weekend cut out for me.
Coolant flush and solenoid replacement.
So I'm going to ask the a question that will probly make all you laugh but here I go. So what gives the error codes?

 

The error codes are given by the check engine light. To check them, cycle the key "on-off-on-off-on" without starting the engine, and count the flashes from the check engine light. All codes are 2 digits, 12 is beginning of codes, 55 is end of codes... these two mean nothing, it's the ones in between them that matter.

Example: "flash...flash...flash...flash...flash...pause...f lash...flash...flash...flash...flash" would be 55.

 

Ok so here is what the flashing lights told me.
12, 15, 52, 31, 55

12 Direct battery input to PCM was disconnected within the last 50 key-on cycles
15 No vehicle speed sensor signal
52 Fuel system rich
31 Evap purge flow monitor failure or evap solenoid circuit
55 End of error messages

I found those postings on this site is there a place to look up the meanings of these?