Th350 C?
 

Will under the truck, I found a Black wire plugged into the transmission. It's a 2 connector type on the passenger side. The black wire is taped off on the end. I thought my truck had the original TH350. Is it a TH350C with a lockup, or is this original and I'm missing stuff?
:canada: :flag:

Could that be the TCC thing?

I think so.

Did our trucks originally have TCC?

starting in 70 I think?
I might be mistaken...it might not have been TCC, but it was some sort of tranny BS that was hooked to the carb or something. I've never seen one since it was normally removed within a couple years.

I bought a '72 th350. It had a switch on the passenger side that sounds like what you are describing. It looks like an engine oil pressure switch and stuck out the side of the tranny horizontally. The switch leaked when I installed the transmission so I removed the switch and plugged the hole with a 1/4" pipe plug. In the research I did at the time it made it sound like Chevy started putting that swith on the th350 in 72.
Later I removed that plug, or the other one on that side, and installed the temperature sensor for my auto meter trans temp gauge.
When I was at the shop last week doing brakes on my daily driver one of the mechanics had a th350c on an engine stand. It had the universal case that fits chevy and BOP. The lock-up switch was on the drivers side and stuck up vertically from the ledge above the pan.

TCS transmission controlled spark...it only allowed the vacuum advance to work in high gear. I think a 350c says METRIC on the pan.