The control pressure is as you describe. The concept, to get it right, is to have your shifts occur before you would naturally let up. If you are letting up the modulator takes a big hit as its pressure varies radically by vacuum. If full load modulator is 60psi, high vacuum might be 15psi.
The reason I bring this up is to help avoid an overly harsh shifting tranny which may be necessary if you overcome this single gear with straight modulator pressure.
PS: relative to the first above paragraph. By letting up, I do not want to infer this to be a full throttle event. I am talking about the activity during your prefered acceleration rate.
[Edited by stevebfl on 07-26-2001 at 07:56 AM]
Bosch Master, ASE Master, L1
33 years MB technician