10-speed 10L80 transmission hard line leaking

EXSlider400 · October 6

2019 AT4 6.2 with almost 100,000 miles. Just returned from a long trip in the northwest territories of Canada and came back to change the oil and the whole underside of the vehicle was covered in transmission fluid. I’ve never seen this before, but the line going into the side of the transmission is leaking. I think this is the transmission thermostat (thermal bypass valve) housing I can wipe off the transmission fluid and watch it get wet and then run down the transmission line. Brilliant engineers don’t assume anything ever needs any maintenance so no dipstick or I could at just at least top it off instead I’m taking my chances driving it to the dealership Monday and until then I have no damn vehicle to drive because of a little transmission leak… and depending on how long it takes to get the parts and fix I really don’t know what I’m gonna do for transportation. I’m lucky when we were up in the very remote areas of Canada (zero cell service) this thing didn’t need transmission fluid.

I don’t know how much the dealership will charge but I know shipping is insane on the replacement lines (GM 85628204) and I believe that’s because it’s LTL. I really don’t have time to be changing the transmission line but I figured I can do it over a weekend because you have to pull the front bumper and grill off as well. On the bright side at least I didn’t change my transmission fluid and filter before the trip like I wanted it to… guess I’ll be doing it now though. Is this a common issue? I searched for a while and did not see this occurring anywhere else. Any advice would be much appreciated. Pictures below or after I cleaned it and it only takes about two minutes before leaking down the line (this is why the truck is not running). Thanks in advance.

Edited October 7 by EXSlider400

EXSlider400 · October 6

Ok… tried to change, just the gasket, but no that didn’t work at all. Wound up changing the hardlines myself and while I was doing that, also changed the filter. I will never in my life do that crap again. Whoever engineered this truck had no foresight of preventative maintenance or repair.

Edited October 10 by EXSlider400