46 RE help!

[dieselnut123]

The truck i'm working on is a 1997 dodge cummins and it is completely stock. When taking off from a stop the truck does not downshift at all, it starts in whatever gear you have selected. It will manually downshift fine except for 1st, the only way it will drop clear to first is come to a complete stop. So far I have checked to line pressure (good), adjusted the TV cable, changed filter fluid gov pressure sol and transducer. I am stumped any suggestions? Oh and no codes are coming up!!

[Mopar1973Man]

Possible speed sensor?

[Rogan]

will it manually upshift fine?Possibly the OSS as mike suggested. It's a cheap replacement part, as well..

[MnTom]

That truck has a 47RE in it, but if the speed sensor is failing generally the transmission will not want to shift out of first or it will try to downshift to first no matter what speed you are at. It sounds a lot like the governor pressure solenoid is your problem.

[Rogan]

That truck has a 47RE in it, but if the speed sensor is failing generally the transmission will not want to ____ out of first or it will try todownshift to first no matter what speed you are at. It sounds a lot like the governor pressure solenoid is your problem.

He said he replaced it.. ? on the move... now Free

[MnTom]

He said he replaced it.. ?

on the move... now Free

Geez, I missed that! sorry...... I found this:

Check your TV cable to be sure its moving fully and comes to full open when the throttle is applied. If the PCM sees too much line pressure the truck will default and go into limp mode and start out in second. I have seen a couple where the 1-2 shift plunger is hung up in the valve body and wont down shift into first. Getting a Scan tool on the truck would be the best bet at this point or else your kinda just pissing up a rope hoping for a answer.

[dieselnut123]

Ok, so the speed sensor, where is that located? All the threads that I read trying to figure this out I never saw this mentioned. If it's a cheap part I will just change it. As far as up shifting goes it seems fine.

[MnTom]

I don't believe the speed sensor is your problem. If it was then you transmission will not upshift. You NEED to get the truck scanned to look for any code(s) stored. Most auto parts stores will do this for free. The problem could be anything from a bad governor solenoid to a bad PCM. On that truck the PCM looks at the TPS and speed sensor in the transmission to determine what gear to be in. If you can get the truck to a transmission shop for scanning. They would be able to see what the trans is doing and hopefully point you in the right direction.