Hey folks,

I had the pan off the rebuilt 4L60e I am using in my swap. I noticed there was an "extra" plug in the harness not connected to anything.

this guy:

https://www.flickr.com/photos/lammergeier/12984461555/

some google image searches found some harnesses have this plug:

http://www.ctpowertrain.com/servlet/...-ROSTRA/Detail

and some do not:

http://www.trutechtrans.com/ACD-Wiri...ND-Basket.html

I want to think is plug is some vestigial organ from an earlier step in GM's evolutionary process, but it's troubling me. The PCM is a 2002 truck, and I bought this trans (from a 2002 truck as well) to match it.

Guide me, o transmission gurus
for it is truth I seek.