When I fill the fluid and run it around it doesn't leak but after it sat overnite it lost about 2 quarts. It seems to be coming from the base of the wiring harness plug-in on the pass side. I've never seen a tranny leak from there. Am I nuts? Or is this what happens when you have a truck sitting around that you never drive

1996 K1500 Suburban 5.7 4L60e w/floor shift 4wd selector

Is there any other source where it could leak from that is above the pan gasket area?

 

Tranny shop sez it's from installing a rebuilt trans that didn't have new clips put on the harness. I guess it's common, so that makes me uncommon. Anyways, I'm sending it to them to mess with. I'm starting to hate that old bomb