1st dakota I have ever owned bought it yesterday and the guy sold me with some issues... I got it to pass emissions with a new cat now I am trying to fix this issue before I blow my engine or tranny driving on the hwy for work.
The switch over the headlight switch for O/D is not working at all. I changed out the switch and still got the same result. After doing some research on the net I shotgunned some issues and changed out the Speed Sensor,Nuetral/Park Sensor and still nothing. The truck is running with overdrive off. I need it to run with overdrive on... I dont do any hauling and would never need overdrive to be off. Please if you know a way I can rig it so I can put overdrive on constant let me know ... I saved 4 weeks to buy this truck and cannot afford to miss work and not drive it also cannot afford a tranny to blow or the engine due to overworking on hwy as I travel 30 miles to get to work. The parts today just about broke me so any and all advice of what to do is appreciated. !!!!!!!!!!!
I went down the hwy 50 mph and hit the switch and the rpms didnt change..I am a pretty good backyard mechanic so I know this overdrive is running in off position.. Thanks to all (p.s. I have paypal gift to the person who can help me fix it )

 

Welcome to DodgeForum!!

The overdrive unit on these trucks is electronically controlled, so there is probably an electrical issue going on rather than a mechanical problem with the transmission.

With that said, have you checked all fuses? Have you checked all wire connections at the transmission? Another option is a bad ECT (engine coolant temp) sensor or a bad TPS (throttle position sensor).

You should start by downloading the 1995 Factory Service Manual....

1995 Dodge Dakota Factory Service Manual PDF
http://rapidshare.com/files/31723895...ICE_Manual.ZIP


Read through that for running tests on the various sensors and check out the wiring diagrams.

 

Yes I checked all the fuses and all the wiring looks normal.. With a test lamp I did check and see the switch for O/D is getting power but when you press it nothing turns on or off. I changed the switch out first thinking it was it. I checked all the wiring to the transmission itself and all checked out fine. I then after reading some forums changed the speed sensor and the nuetral/park sensor on the tranny with no luck. I am seriously at a loss why I am stuck in overdrive off and would love to know how to get it into overdrive on constant. Is there anything I can unplug or jig up so it is in constant on? If you could help me I would super appreciate it.. I just did a tranny pan drop and filter change and def need to preserve the truck..I saved 4 weeks for her for my home business and she is all I got..I cannot afford to drive it down the hwy 20 miles to a job and have her breakdown.. Please advise.

 

sorry sir the link isnt working can you please give it again. thanks

 

Forgive me if I'm way off here, but it sounds to me like you don't understand what overdrive is?

Overdrive is the transmission's fourth gear. Actually, any gear that is higher (numerically lower) than 1:1 is considered an overdrive gear because the transmission is being "overdriven"... in other words the output shaft is spinning faster than the input shaft.

Now, the automatics in these trucks are based off the old TorqueFlite 3 speeds. They were turned into 4 speeds by adding an electronically controlled overdrive unit in the tailhousing of the transmission. Gears 1-3 are all controlled hydraulically, that is, when the governor and throttle valves tell the transmission it's time to shift, it shifts. Fourth gear (overdrive) is locked out by the computer until the computer decides it is ok to make that shift. Speed, engine temperature, and throttle are the 3 main things the computer looks for. When the computer decides its ok to make that shift, it releases the "lock" on the overdrive unit and the shift is then allowed to be made when necessary. It is activated hydraulically like the other 3 gears.

The only thing the button on the dash does is override the computer's decision to allow the shift into overdrive.

Check to see if your computer throws a code 17, and if it does, change out the ECT sensor. That is one possiblity as to whats wrong.

 

http://rapidshare.com/files/20546066...AN_SERVICE.ZIP

Just out of curiosity, is your torque converter lock up clutch locking in 3rd gear at all?

 

Yes I used to have a cav. when I pressed overdrive button to off/on it would put out higher rpms and slow the car down with more torque. This truck is the same way and I agree when I go down the highway at 50 mph it is showing 3K rpms. and slowing the truck down quickly as if I was driving with tow package or what I thought was overdrive off .. The temp guage on the truck works fine and slowly goes to warm when driving.(is this the same thing as you specifiy?) I will check some of the tests you specified . I did the (code check) by turnng the key and it shows sooo many friken blinks its hard to keep up. I do think the first one is 17 next one is 3thirty something. I will def give it a shot first thing in the morning and keep u posted. I totally appreciate your help.. So you think this may cause the switch to not work at all? I seriously just dont want to put all the wear on the engine or tranny. The fluid smelled somewhat foul and the engine lifter has a slight tick. Driving it without the overdrive will cause this truck a early grave... Thanks again ill keep u posted.

 

Well, there are two coolant temperature sensors on these trucks. If you look behind the accessory bracket on the intake manifold next to where the upper radiator hose is, there will be two sensors there. One has 1 wire, the other has 2 wires. The one with 1 wire is for the gauge, the one with 2 wires is for the computer. If the gauge is showing normal behavior, and you are getting a code 17, I can tell you with 95+% certainty that the 2 wire sensor is bad and that is what is causing your OD not to work.

And about my above explanation... I just wanted you to understand that the switch only prevents the shift into overdrive, it doesn't directly control anything.

 

Ok once again the old saying from our parents. You learn something everyday.!!!!!!!! So I will def. go to the junker and get that first thing in the morning. The torque converter seems to be shifting fine through all gears normally just not getting to the 4th gear because of the O/D issue. If after I change this sensor and it is not it then ill be changing the throttle position sensor? it is located on the trottle body I suppose. If for some ungodly reason these are not the problems do you have one more maybe you can throw to me? I would totally appreciate it as these two issues seem to be easily fixed and I would love to hunt down other issues if possible.... I seriously will love it if I get into the truck and see the overdrive is off/on would make my day,month,year, thanks for all your help. ill let u know tomorrow how goes it...Gary

 

I don't know of anything else electronically off the top of my head. If its not the ECT or TPS, and you've already replaced the speed sensor and checked fuses and wires, then I think there is something wrong inside the transmission.

But again, don't worry about it... replace the 2 wire ECT and I can almost guarentee you that it will work again.

I did an auto-manual swap on my truck about a year ago, but I do remember one time when it was an automatic, my thermostat broke and was stuck open and the truck couldn't get up to temp and I didn't have overdrive cause the required temp wasn't reached. In your case, the required temp is being reached, but the computer doesn't know about it cause the sensor is bad.