Finally got a chance to start working on the new JK. On mine (2018), the t-case vent is in the same place it has been since 2007, between the engine and firewall. As for the auto trans, it has it's own vent and it is already extended all the way up to the top of the engine next to the intake. I extended the t-case vent to this same location. I don't see anywhere that water could get in to the transmission. Hopefully I'm not overlooking another vent, hole, etc.
18 JKU Granite Crystal- 4"lift, 40s, UD60s
07 Red Rock Crystal JKU - Sold