Speed sensor-shifting problems
 

Hi, New to the site, looks lke a great one. I have a 1997 F350 motorhome with a overdrive auto transmission. The trans. started shifting hard and the light started flashing on the overdrive control and I had no speedo. It even went into neutral, I guess, because I had no gears at all and then it came back to where I had gears. I unplugged it and I had all the gears but it shifts hard with no speedo and overdrive flashing.I replaced the rear end speed sensor and it fixed it, for a while and then it started doing it again. Could I have a bad sensor, could the fluid need changed or I have read that there is a sensor in the transmission also. Sorry this is so long just trying to give as much info as possible. Appreciate any help, going on vacation in the West Virginia mountains in a couple of weeks, hate to loose my tranny.

I hate when a tranny gets loose! Then you have to chase it down, bring it back, reinstall it. It is almost as bad as when you lose your trans. Then you have to rebuild it. }>

Yes, you could have installed a bad sensor. Nothing built by humans is perfect. It is about as likely as winning the Powerball lottery. It can happen, but it isn't likely.

It is MUCH more likely that there is something wrong with either the wiring between the computer and speed sensor or the dash computer which is called the PSOM.

Read this to see how you can read the codes stored in your computer. That is the best way to start to find out what's wrong.