Engine/Transmission (1994 - 1998) Overdrive acting up

[starring]

95 2500 4x4, ATS transmission and torque convertor, staight piped I took my truck to Cummins in Grand Rapids to get the engine tuned up. When I got it back the transmission has been loosing overdrive on and off. Some times everything works fine, but usally i have to wind it up to 65 to get into overdrive. Any ideas?

 

[ronco]

starring, you should try searching for your answers first. There have been a lot of discussions on this subject in the past. Bottom line, sounds like your throttle position sensor (TPS) may be dirty. It could also be your trans. temp. sending unit. Anyway, run the search and you will find possibilities and how to troubleshoot. HTH





Ronco

 

[tp0d]

sounds like they might have checked your throttle linkage and de-tuned your TPS... . (could be dirty also, but if you say you have to goto 65 to get into OD, this could be it)



Loosen the throttle linkage screws (2) about one full turn. Then twist the outermost small plastic box (its about 1. 5x1. 5" square). This is the TPS. You want to twist the TPS towards the front of the truck, or counterclockwise when looking at it. To make your TPS lock up earlier still, remove the wiring and bolts, then use a small rat-tail file to eggshape the two mounting holes, so the TPS will rotate more counterclockwise. Dont do too much though, and try small adjustments at a time. I did this to mine, makes the truck drive like a completely different beast... Only turned it forward about 1/8" tho... You definetly want to clean that sucker with some TV tuner cleaner while yer messin... radio$hack will rob ya $10 for it tho



good luck



-j

 

[Andy Redmond]

If Cummins adjusted the throttle linkage(s), this might well have disturbed the TPS setting. Cummins' techs should know how to adjust the linkgage for proper travel and still get the TPS where it needs to be. Usually 1 volt works well at the idle setting and you should see an additional 3-3. 5 volts at wot. (Ign key on /engine off).



Maybe you'll get lucky and something electrical got disturbed. Or maybe they did you a favor and steam cleaned the engine and now you have moisture in the tps or an electrical connection.



Good luck and let us know what you find that the gremlin was. .



Andy

 

[Howard Durand]

Check your electrical connections and ground wires. Most of the engine sensor grounds are connected at a bolt in the head on the driver's side of the #1 cylinder. That would be a good place to start.