Three problems worked together in my case:
1- Import Motors in oakland charged me a good deal of money to twist the VCV to 10" and crank the modulator a few turns.with no apparent attention to spec, so the vacuumw as preset to 10" all the time. Worked okay with their lousy modulator adjustment, but not on the rebuilt trans.
2-There was a clog in the restrictor leading to the VCV. That's right, a piece of crud holding the vacuum high.
3-Several connections were worn out and leaky, so I purchased new tubing AND restrictors and replumbed it all.from the factory diagram.
Seems to be fine with the original blue saucer. It would be nice if anyone actually new what was inside--but no one does.
1987 300D Turbo 229k (+)