Challenger 37ND Grey Tank configuration
If you are already aware of this I apologize.
The Grey tank configuration on my 2015 37ND is as follows.
Kitchen and bathroom sink are plumbed into the main grey tank while the shower and outside kitchen sink are plumbed into the rear grey tank.
I determined this by running water at each fixture (one at a time) and seeing which tank the waste water flowed into.
Prior to buying the coach a Thor rep told me by phone the rear tank was for outside kitchen only. Apparently their reps don't know how their products are produced.
US Army (Ret)
2020 Entegra Accolade 37TS
2019 Jeep Grand Cherokee Trailhawk (Toad)
FMCA - F432054