shower/tub not draining

Hello
My shower / tub is not draining and im not sure how to fix it with out a major piping job. What I have is the drain comes down from the tub about 1’6†into a 90 then about 1’ it runs into some kind of box, then it goes out the top of the box about 6†to a 90 and then about 4†into a tee. The top I believe is a vent and the bottom 90’s and then goes for about 4’ into the main drain for the house. I don’t know what the box is and I believe it is my problem. I have a pic of it to help everyone to understand what’s going on.
My question is What is this box and how should I go about fixing it?

good picture. Drum trap is your box. AFAIK.

i believe that device is a drum trap.

Do you know the purpose of "traps" in drains? Check this out, and you'll find that only P traps are used these days. Drums are too boxy, cornery, and sudden-changy. P traps' shape lets water act fluidly and slide gracefully through it. The shape also lets you clean it out more easily than a drum.

Take more pictures, so people can get an idea of the height issues you have. Replacing your drum trap with a P trap that makes sense (fits the space) is a challenge for a DIY person, especially since i think i read something about a six inch riser coming out of the drum trap before the drain goes horizontal... Not sure about that last part of your message.

david

Thanks for the response nice to know it’s a drum trap. Yes I have a basic knowledge of plumbing. I don’t know if I can fit a p trap in the space I have. I was also wondering if the drum trap is installed upside down? Does it even matters. I think I am going to see if I can go to a p trap. I am thinking about installing a plug in at the T. There is a cap right where it 90’s that goes to the drain and I am thinking about trying to attach it to the tub with a p trap. I might have a little up hill slant with the pipe but it should still work.

I got the drum trap to open and I cleaned out the pipes. I found a spring that was about 1.5 in long and 1in dia. There was a big hairball stuck to it. Now my question is, what can I put on the plug to keep it from seizing up incase I have to open it again. It took me some effort to get it open this time.
Thanks Jason

plumbers grease...
That is what is usually recommended...