In scanning this thread, I don't see where you list any issue?
What is the issue?

The vacuum modulator is a common failure item.

Transmission shifting is effected by almost any vehicle vacuum leak, excluding the central lock system.

.

__________________
ASE Master Mechanic
asemastermechanic@juno.com

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
1984 190D
2003 Volvo V70
2002 Honda Civic

https://www.boldegoist.com/

+1 The VCV, the Vacuum amplifier (blue UFO), and the Vacuum modulator are all part of the same system. As the name implies, the purpose is to modulate shifts. When out of adjustment or malfunctioning, shifts will be harsh.

The shift points are primarily controlled by the valves in the transmission's valve body and the torque converter. Changing the spring rates will change the shift points and spacing. A problem in the valve body can cause stacked shifts or missed shifts. If the transmission is otherwise operating normally, the entire shift pattern can be moved higher or lower with the Bowden cable.

Neither the Bowden cable nor the vacuum modulator are especially problem prone. Most adjustments get done because if you have a knob, you turn it. Sometimes you even get lucky and the issue goes away. There are exceptions, but vacuum leaks are the root cause of most modulator issues.

reply # 15
READ Brotherton's article until you're (Impersonal you) Bored to Tears,then stand on your head (Altered Perception A.K.A. POV) and read it some more!!!
Put it under your pillow for a week and mayhaps more info will "Osmosisize" into
your cranium.
LOTS to comprehend!

__________________
'84 300SD sold
124.128