I've got an '82 300D Turbo and have determined that the vacuum modulator unit isn't holding any vacuum. I tested this with a MityVac with the engine off. I'd like to replace the modulator, but read that I need to follow the MB instructions to prevent transmission damage. I've got the W123 Service Manual, but it has no section for Transmissions, and I can't find these instructions anywhere. I don't want to pull out the old modulator and swap with the new one if there's more that needs to be done. Does anyone have a copy of these instructions anywhere?