'74 450sl vacuum modulator adjustment

[halw540]

I need help setting up a new vacuum modulator in a 722.004 series (3 spd auto) tranny in my '74 450sl - this is the metal modulator with the allen head adjusting screw behind the vacuum banjo fitting. I know turning it cw firms up the shift and ccw softens it. What I do not know is how to set the adjustment screw initially. Thanks in advance for your help, Hal

[Mike D]

The "proper" procedure involves a "T" fitting installed inline with a gauge. The "real world" procedure is to install the modulator, drive the car and make adjustments as needed. Do the adjustments in no more than half turn increments.

[halw540]

Update on adjusting this style modulator - I measured the distance from the back of the old modulator's mounting nut down to the allen head adjusting screw then set the new modulator initially to this value (0.55" on my vehicle). This turned out for me to be very close to the setting needed for good shifts.