99 mazda protege transmission

Question by tammymcghee posted 7 months 2 weeks ago in Mazda

Car started off needing seals from leaks.  Did that but, I can clear the OD blinking light and car will shift through gears but reving up between 2nd and third gears.  Car runs at 2700 rpms but goes up to 3900 rpms when trying to shift higher gears. When the OD light comes back on, car wont shift into overdrive.  Solenoid good. Fluids good, seals and bearing replaced, new oxygen sensor.  Transmission was replaced last year with a junk yard one but must be slipping. Sometimes it won't start up without messing with negative battery cable? I love this old car.  Any suggestions what to try before replacing transmission?  Pic is a sensor? There is a vaccuum line attached. Is that correct to do? I know I sound clueless,  but I am hehe. Any help plz.