There should be some type of access panel to get to the drain. We don't have your model, but on our TT, there's a section on the wall that looks like a frame of molding. The top piece is attached to the center of this panel, and it slides straight up and off, to reveal the back of the tub faucet, and tub drain plumbing. I've seen other TT's that had a section of paneling that came off with 4 screws.
2012 Jay Flight 19RD
2016 Ford F150 XLT 2X4 SC 3.5L Eco Max Tow
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1 Spoiled Dog