My 1984 500 SEL is also in need of tranny adjustment. I´ve spent the last week trying to adjust the modulator to find the right setup.
I adjust the transmission in the evening and drive it a day or two to asses the change before doing additional adjustments. It seems as if the shift-quality does not change very much when I turn the T-handle (about 5 clicks per adjustment), which makes me belive that something is wrong with the vacum lines or the modulator itself.
Now to my question - How do I check the modulator and what vacum should the modulator see (I assume that You check it at idle)?
Please help me with help for troubleshooting.