Today I felt a "kick" again .
the TransGo shift doesn't help . every shift I feel (high frequency) , and stronger

What could be the problem ?

I had problems and had a trans shop read the codes and even though no light was tripped, found a history of stored transmission codes, one of which was P1811 long shift.
I also installed the Transgo kit but with much success.
Varnish does build up in valve bodies/solenoids, and you could try adding some Seafoam Trans Tune, which in short order may clean things up a bit.
I would want to see what codes may be stored as well.