I have a double sink less than 10 yr. the run line from the sink to the vertical wall shaft is clogged.

I have tried drano, remove traps (very clean), have strong snake from HD.
But when I feed it it only goes up the vent line not down the line.

I have access to the wall behind the sink, if I mess with the drywall. Should I open the wall and then then cut the pipe, or call a plumber to avoid the wall mess because they'll have magical powers to clear the clog?

I think the builder's plumber didn't change the drain line slope when the sink and D/W were swapped and the run was made 2 ft. longer than usual, so even if the clog is fixed, it might reoccur if I don't fix the drain slope.

Thanks for the help.

That horizontal pipe going into the wall should be joined to the drain with a WYE, apparently it is upside down or they used a T. I don't think a plumber has a magic tool for getting past this but you are welcome to get 3 bids. I'd open the wall and see for myself.

I saw the wall before it was closed, the run is on the left, the flow from the right bowl is on the right. I think the snake is going up or to the right then up into the vent.

Is there some trick to get the clockwise snake coil to turn left toward the clogged section? I'm willing to cut the trap's downward facing 90 end piece so I have a straight view into the pipe as it enters the wall.

If you don't want to snake from the roof vent then attach a drop head auger tip,(see image). When the snake hits the vent the tip will direct the snake down. Good luck, Tom