2004 Tacoma Rear End Cable - Identification

[JackMan]

Hello folks, trying to figure out what this is, In red. Ignore the drain fill plug lines.

Thanks

 

[tacojoel]

If you mean that upper red line...I believe its a load sensing spring like I had on my gen1 tundra.

Maybe jay can chime in, He's way more familiar than I am on these gen1 taco's.