I'm still looking through the ATSG manual for you - I started to read it last night but then I fell asleep...

According to the book, the vacuum controls the "modulating pressure" which in some way or other is connected to the "regulating pressure". The problem I have with the ATSG description is that it seems to be based on the transmissions with the regulating lever assembly - i.e. the whole Bowden cable thing again...

I'm planning to re-read it and see if I can shed some light on the problem today but I guess I'll have to visit friendly head mechanic at the dealer again (poor chap!).

(Oh by the way I'm particularly interested in clearing up this problem as I've got the same system)

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!