No Speedo or Overdrive,,,,Sometimes!

[3dracer]

On my 'ole '92 CTD,,,,,,Sometimes the speedometer won't register and when this happens, the overdrive won't engage. If I put it up in neutral and shut it off and restart, it sometimes will work... . Other times I have had to ,,I really don't like to do this :-laf ,,,Push the throttle wide open and it will work. Some times neither will work, I have been told there is a pressure switch somewhere on the auto trans that could cause this. Any suggestions? :-laf

 

[cerberusiam]

Speed sensor, gear for speed sensor, shaft in the speed sensor. Any or all willcause the symptomsyou decribe. As well as bad wiring, loose or bad connection, and/or bad ground. Other things also but those are the usual suspects.



Start with the speed sensor on the back of the trans, check wiring and connections.





Good luck.

 

[dpuckett]

I have a similar problem in my 92, though I havent noticed the cruise acting up (oh yeah, I dont use it in town). The speedo will register from dead on to about 75% low. Really hurts MPG numbers . The cause of it on mine is the drive gear on the transmission output shaft is no longer tight on the shaft- it slides around, spinning the driven gear slower, and giving an inaccurate reading.



In my experience, if it is the speed sensor, the speedo needle will literally be all over the scale 0-100. But is a wire is loose, or you have a gummed up connection, that will casue your symptoms, too.



I wouldnt think your speedo issues would be related to the transmission or any switches on it. The cruise not acting right with the speedo being erratic go hand in hand.



Daniel

 

[jwilmoth]

I went through the same thing for 2 or 3 yrs. Seemed worse in hot weather. Took speed sensor off cleaned all the grease off and cleaned plug no prblems since.