Transmission kicks down, won't upshift

I bought a 1981 300D, and replaced the old transmission with a working used one. At this time, the car runs smoothly, however the transmission kicks down into a lower gear too often/frequently. Instead of going into 3rd from 4th, it drops to 2nd, etc... It delays upshifting, lifting off the accellorator helps... Also: The dash lights, climate control, and radio do not work but the fuses seem fine... Any Ideas! Thanks!

Forums

Chassis Model Number