REDWOOD Has no manuals on any of their systems or schematics either.
They just don't keep them, since the model year is constantly changing.
Which Grey Tank do you need to replace? And what is wrong with it? Cracked, Leaking?
If it is the Grey Tank on top of the Black Tank, plan on shelling out some major money.
My Black Tank was not installed correctly and 2 small cracks developed on the corners of the tank, it is a Fiberglass tank and the estimated cost for just the tank was $325. Then you have to get it into a shop to have it removed and replaced.
I have repaired the tank myself and so far so good!
But, as I said, be prepared to shell out some big bucks!