I have a 79 300sd that was my daily driver. The transmission worked flawlessly, no flaring, no slipping, perfect. A few weeks ago I shifted the car into low gear and the transmission will no longer up shift.The car starts in 2nd gear when the shifter is placed in Drive I can use the shifter to shift into 1st gear but cannot get the transmission back to 2nd without going to Park first. The transmission goes into gear without hesitation when put into Drive and does not slip and reverse still works. I have unhooked the wire from the kick down solenoid and still have the same problem. I removed the valvebody to inspect and clean it. The center band (B-2) in the transmission seem to fit looser than the other 2 could this cause the problem I am experiencing? Does anyone know what valves in the valve body affect the 1-2 and 2-3 shifts? Is there a procedure and specs. for testing the governor on these transmissions? Thanks in advance for any help.