Hello I have a 4l60e Transmission in a 87 k5. Was dropping the pan and filter yesterday and saw this part broken off and ziptied as shown in photo and was wondering what the little tube looking thing thats hanging is called. Any guidance would be much appreciated thank you. If you could also identify what the 2 brown pieces that part is connected to is called that would be great.

 

Just a guess, but appears to me that the EPC solenoid has been bypassed and replaced with some sort of a (non-electronic) pressure solenoid (the gold colored part behind the head of your arrow). The electrical connector was then split (2 light brown pieces) and appears to have been connected across some sort of resistor (little dark brown tube thing) to try to fool the PCM into thinking it was still there. Maybe it's because 4L60E transmissions didn't come in 87 K5 Blazers? Part of making it work?

Watch the start of this video and you can see what is supposed to be there. I say if it shifts good, tie it back up and leave it.

 

Looks like it has one of these Transgo kits in it. Recognize the "tube" and the head of the modulator looks like yours.
https://transgo.com/product-details/46-mod/