Transmission at times does not shift from lower ranges

Either cases when fuel system or transmission sensors register an anomaly the fuel injection controller (ECU) and or transmission controller will send the tranny to limping-mode.

Possible cause:
Check out for any engine sensor malfunction or look for vaccum leaks they could take controllers to limp-mode as well.
Most likely: and this is my best guess:
1.-Engine got air. (Cooling system) purge (bleeding) cooling system, find out air source
2.-Transmission relay is worn out. Should be replaced.
3.-Dirt or oil at wiring connectors that is running voltage to transmission solenoids valves from transmission relay.

Likely:
1.-Transmission controller needs software upgrade. (Lates firmware)