I am finishing up my swap, 4BD1T to a TH 400/NP 205, and I need help with the vacuum modulator. Allegedly, a TH 400 that was connected to the 6.2L diesel motor from the factory & the CUCVs had some sort of vacuum source that modulated the amount of vacuum needed to shift normally. This set up also allegedly used a different modulator set-up. My TH 400 was originally attached to a 454. Does anyone have a straight, NON-BS answer to this problem? I have looked at this forum and 10+ years of info makes my head hurt and answers hard to find. Google was also minimal help. Thanks!