Water leak though only after using bathroom sink

[mitsured]

I'm planning on dropping the belly of my Tracer Air M-250 this weekend though I was hoping I could get some advice on what type and how big of a mess I'll be getting myself into.

The issue I'm experiencing started on our last trip. If we use the bathroom sink the belly of the trailer start filling up with water and eventually over flows into the ground.
After I noticed this happening we stopped using the bathroom sink. We could use the kitchen sink, shower, and thank fully toilet without any further water leaks.

By belly I mean the corrugated material that covers the bottom of the rig.
Not sure if belly is the right term though sounded good in my head.

I've never worked on plumbing below my rig before though I'm guessing the drain hose connect to the top of the tank?
Is there a nipple fitting with a hose clam or a different type of connection into most trailer gray water tanks?
What's the likeliness of me being able to fix this without dropping the gray water tank?

[mitsured]

O I for got to add I did some searching and didn't find any info that matched my situation. If there is a thread I should see rather than starting a new one please share.
No need to start from scratch

[mitsured]

The issue ended up being the sink drain at the grey tank. I guess it was not glued on well from the factory and had separated and moved towards bathroom sink. So my theory is that only the bathroom sink leaked because the open part of the drain was closest to that sink so when the water flowed through the drain it just missed the gray tank opening. After glueing the drain back on I've had zero leaks. Side note I "love" how the gray tank opening are right next to my fuze/breaker box/converter. I know drain pipes don't have high pressure though having the drain pipe touch a box full of electronics seems like a bad idea.

[NJKris]

Would love to know how you ended up fixing THAT! I imagine you had to drop grey tank, but no idea how it is plumbed in. Is it just a friction fitting? Would be impossible to reach any coupling I imagine.

[mitsured]

Originally Posted by NJKris

Would love to know how you ended up fixing THAT! I imagine you had to drop grey tank, but no idea how it is plumbed in. Is it just a friction fitting? Would be impossible to reach any coupling I imagine.

I was afraid I might have to drop the gray tank which would be a nightmare.

I should have taken some pictures. I did some fishing around with a scope camera to find out where the drain pipe was running.
I ended up removing the "power center" where the fuzes and breakers are located and just to the right of it was the drain line going into the top of the gray tank. Mine had an ABS black plumbing piece sticking up. The drain pipe from the sink was just sitting on top of it. I just got some ABS cement and glued it back on.

I don't know if they didn't/don't glue it from the factory though I checked all the other fittings and they were glued so maybe they just forgot this one.

I also taped the gray tank fitting to the floor around the pipe because they WAY oversized the hole. I'd say there was at least 1 inch extra all the way around.