so i don't have a TPS or the factory wiring from the TPS to the trans, thanks chip(ofelas). so i have to wire up the POT to the trans anyhow but all of the "how-to's" i find are for wiring the POT to the factory TPS wiring harness. anyone know how i wire it direct to the trans? thanks in advance! cheers

 

transmissions and wiring scare me. lol. I have the on/off switch for the shift lever and a potentiometer and not a dang clue what to do with either. this is why god made manual trans.

 

ok. so the POT only controls the shift point between 3-4? so when the trans shifts in and out of overdrive? i guess i'm confused where the 3rd wire goes? can i just run 12v to the POT, then out to the on/off switch, then from the on/off switch to the 2 pin connector on the trans? with the other pin on the 2 pin connector to ground?

 

The pot is normally fed 5V from the PCM, and the center wire goes to the PCM and normally ranges from about 1.5V and 3.5V if I remember correctly. The PCM shifts the OD solenoid by pulling one terminal to ground. The other solenoid terminal is connected to 12V key on. None of the wiring from the pot goes to the transmission.

Without a PCM you can do roughly the same thing with a pressure switch. There's a thread on that mod on this site.

 

A pot will not control the trans without a PCM. All the pot does is supply a variable low voltage signal to the PCM. With no PCM a pot will not control the trans. The OD solenoid is looking for a 12 volt power feed and a ground on the second wire.

So you need to use pressure switches to control OD.

 

ok, so i can use the on/off switch on the shift lever wired to the 2 pin connector on the trans but the POT is useless and i need pressure switches. searching for that write-up now. man, i love this forum, lol

 

https://www.dieseltruckresource.com/...fix-od-156988/

found it. answers all my questions, haha. thanks again guys. he even includes the wiring of the on/off switch in his write-up.

 

I have my CTD RamCharger wired up to shift OD via an old school dimmer switch on the floor. I was hoping to use a pressure switch like the sticky but my trans pressure is way too high (the trans was built for a pulling truck) and I wasn't able to find a switch that suited me.

 

Is a 10k pot to big for the bypass ?

 

I would like to point out that a POT can be replaced with two simple resistors in series. The junction of the 2 resistors would correspond to the center (wiper) of the pot. Just select the 2 resistors to give about the voltage you need. For example if you have 2-5K resistors to represent a 10k POT and applied a voltage to them say 5 volts there would be 2.5 volts at the junction.

Edwin

 

I hooked in to the wiring harness from the tps to the 10k pot was that correct to do ?