333E steady drip machine side case drain coupler

[Barthski]

so i was out brushing one day and snagged the case drain line on some crap and snapped it at the manifold on the boom. I replace the coupler with a deere part and ever since it has dripped while using the machine. its not a lot more of an annoyance than anything. I've been told its one of the other two couplers that are bypassing pressure through the manifold and that's why it leaks. Any way to test it? the manifold itself seems fine and it drips right out of the case drain coupler not from the manifold.

Thanks in advance