BE CAREFULL WHEN REMOVING THE MODULATOR VALVE!!
If you are working on a A4LD trans or C3 there is a rod that sticks inside the modulator valve which goes into the valve body. It's about 3/32" diameter and about 1/14" long. Don't lose that pin or the trans will not shift ever again.
It's a pushrod that connects the vacuum modulator valve to the shift modulator circuit in the valve body. I learned the hard way and had to crawl under my truck for an hour to find it (and making sure the landlord doesn't see me doing tranny work in his parking lot!!

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