1997 altima automatic tranny problem

I hope this is simple here goes. I just bought this 97 altima, the best part of the car was suppose to be the transmission. It was recently rebuilt. The car has 168,000 miles on it, anyway it backs up fine, when you put the car in drive it never tries to go in gear, I can move the selector to 2nd or 1st and it will take right off. Once you get up to around 20 mph it will go into drive and overdrive and run any speed you want, but if you mash down on the throttle the motor overrevs. I checked the transmission codes using the self diagnostic procedure in my manual and it shows a revolution sensor fault, I think I found this sensor but I have no idea if this can cause such a problem or what it does. It had one long flash then 9 short ones. Any Ideas? Also the check engine light is on but the computor showed no codes. Thanks :confused: