The modulator is on the drivers side front of the trans. It is plastic and will probably be green in color.
In the center is a black rubber cap the diameter of a nickel about a quarter inch tall. The cap easily pops off, under it is a castelated circle. There is a steel tee handle locked into two of the castelations. The tee handle easily is removed to the point the castellations no longer keep it from turning. Once in this position screw the key one full turn (maybe more) clockwise and push back into the castellated locks. Replace the rubber cap and try it out.
The adjustment is reversable as long as you keep count. You probably can't hurt anything no matter how tight you get it. I have seen the result of over pressure: it brakes the second gear band servo piston which is one of the modifications done on a proper rebuild anyway.
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician
[This message has been edited by stevebfl (edited 05-12-2000).]