Most people don't understand ground or bonding cables carry current; they are parallel circuits. And why you can have too many grounds.

If the ground point on the front of the block degrades, current will flow through the transmission with the added ground strap, especially with the starter engaged. You have to potential then of flowing ~500 amps during starter engagement if it is really poor. But since this is now a parallel ground/negative path, some current will always flow through it. Adding the cable does exactly what it is supposed to prevent.

There was a TSB early on when the stud up front was undersized and under torqued. As a side note, when this connection degrades is when the braided cable from the frame to the cab under the passenger footwell burns up. That cable always flows some electricity as I've shown in one of my videos. It's called a bonding cable, but it is one of the multiple flow paths, especially when starting. It doesn't need to be upgraded, the connection at the front of the engine needs to be maintained.

Ford is aware of the issue and mentions in the body builders book not to run any negative or ground cables to the transmission. This is for situations of adding a winch, manliest, or other device by the body builder. But it is the same situation with the starter. Current will flow through every parallel circuit (ground).

I can't find that reference right now - I was up most of the night and my brain is fried. But here are some slides from my videos.














The video where I discussed all of this. I don't know is there are subtitles in German.



Those bonding / ground cables are very active. And any you add become another path.