Classic/Antique Car Repair: Tranmission 63 Cadillac 390ci 3sp auto, Automatic transmission wont upshift


Question
Transmisson will not shift out of first gear. Have tried to manualy shift to no avail. Fluid level is correct and looks clean no burnt smell. Checked kick down linkage for binding and adjustment. If going down hill car will gain speed while in the L position but will not up shift if moved to the normal drive position. Could it be upshifting but Torque converter not locking up.

Answer
If you can feel the detents as you move the shift lever through the positions, the shift linkage is connected to the shifting valve inside the transmission, which indicates that the problem is internal, probably a piece of debris has hung up somewhere in the valve body or perhaps in the governor, causing the transmission to stay in low gear.

If you cannot feel the clicks as the shifter passes over each gear, the problem is most likely in the shifting linkage - preventing the lever from moving the shift valve through all its positions.

Your transmission does not have a lock-up torque converter - if the car moves at all, the converter is working.

You will have to get the car to a shop which is willing to diagnose it for you.

Sorry I can't be more help.

Dick