Transmission electrical cable

[1967 satellite]

On a 727 transmission there is a cable running from the starter solonoid to the side of the transmission. What is this cable called and where can I get a replacement.

 

[451Mopar]

If it is the three prong, it is combination of reverse light and neutral safety wiring.
If an early (pre '70? I think) single wire, it is just the neutral safety.
Most likely you are asking about this:
https://www.summitracing.com/parts/...MIjOSnycKc4gIVE73sCh0rkQ_LEAQYAiABEgLPX_D_BwE

 

[JimCoronette]

Assuming it's for a 1967. They had the single pin connector compared to the 3 pin in 68.

http://www.evanswiring.com/catalog.htm
Half way down under "Transmission Harnesses"