I have this TH400 shortie in my 72 MC. When cruising under 55 the trans seems fine. No leaks, etc.
The problem is when I run Sherleen upwards of 55 plus the trans start leaking through the seals.
I replace the speedo gear, governors and all gaskets. We I'm home and check the source I'm finding
the leak is pushing through the pan gasket around the vacuum valve. No overdrive, 3.73 rear possi, shift kit. The pan is straight, no warp or cracks. We went as far as using the black silicone on the pan itself. It lasted for a few runs but in the end it results to the same leaking issues only over 55 mph.
