Hello Terry and
to the forum.
Your problem might have nothing to do with the automatic transmission at all. For smooth, correct operation they rely upon engine tune, so the first thing I would do in your shoes is to check things like the sparking plug gaps and their condition, air filter, vacuum and breather hoses for security, exhaust system for leaks, etc. The gear changing technology is actually quite complex. On changing up, the engine's torque is reduced by altering the ignition timing. This gives the 'soft' quality to the change which can sound like a well executed manual gear change.
I would next consider the automatic transmission fluid. When was it last changed? If it has been, was the correct N402 spec fluid used? Is the level correct?
The other possibility is a problem with the multiplex communication system between the engine and automatic transmission ECUs. T4 could help with that.
Your symptoms don't match those of the solenoid failures we've encountered although anything is possible.
The chances of a torque converter fault are extremely remote.
Simon