I will attach some information showing the test points for the transmission pressures.
Adjusting Transmission Modulator Pressure
Just realized that you probably have a 722.1 transmission.
The info I posted is for a 722.3 transmission.
The procedure is basically the same for a 722.1. The modulator pressure is 3.0 bar. To be honest with you I do not use a pressure gauge. I make sure that the valve is getting vacuum and then soften or firm the shifts by adjusting the modulator valve by feel.
Turn the adjustment in to firm up the shifts and turn it out to soften the shifts.