OK guys, I'm new to the form not new to working on trucks lol. I've been having problems with my 2001 ram 1500 5.9 4x4 [off road edition] truck has 119,205 I bought it with 93k love my truck, I drove up to home depo three weeks ago and I was on the freeway for a mile and noticed that it started hunting up and down in over drive then kicked me out of overdrive and wouldn't let me back in no lock up. so drove back home and checked fluids and looked fine no CEL also changed the filter and fluid dropped pan looked good too while I was off work for the day, so long story short it threw a p0720 output speed sensor so replaced it and felt ok for a day then it started acting funny again p0720 again so thinking it was a bad part in a new box I swapped it out again plus a new pig tail for the sensor. cleared the code and came back right after. so I did a live scan and it looks like it is loosing signal to pcm only some times it will read 0 intermittently! so I looked threw the harness thinking a wire damaged somewhere but cant find anything... now I'm going nuts I'm starting to think maybe its one of the transmission solenoids, reading a lot on the internet seems like its a reasonable thought. not sure if maybe one of the solenoids would cause the OSS the throw a CEL due to one of them failing or not, I know a lot of u guys know a lot more then me on these trucks but I'm out of ideas. my wife wants me just to get rid of it and get something newer but I like my truck please let me know what u guy's think.

 

Pcm needs the speed sensor to be able to shift the trans. Sounds like a loss of connection issue, Need to check connections at pcm or the continuity of the wires going to the speed sensor. Also what brand sensor did you install?

 

I did check the pcm plug and pins and know what wires are in the plug that go to the oss and didn't see anything there. How would I check continuity?

 

And the first sensor was a duralast (autozone) then the shop that looked at it put something else in I'm sure a aftermarket auto parts store one also. Would a mopar one make a difference you think on this particular sensor??

 

Are you getting 5 volts down at the sensor?

 

My brother comeing over with meter what should I be getting and how should I be doing it u think I'm not a electrical master lol

 

He dose well will electrical and finding problems I mean I'm do vary good. His idea was to cut the two wires off the pcm that to the oss and tie into new plug and then two new wires to the pcm harness to bypass the factory circuit

 

A scanner would be the better tool. See what the PCM thinks trans temp is doing.....

 

We are not getting 5v on the sensor. 2.56v at the sensor

 

Bad connection somewhere. Test at the PCM, see what's coming out there.