Q&A

I recently had a new transmission replaced. I guess in taking things apart, well things happen. but now when i drive, the ever present exhaust that used to come out the muffler is gone, it now comes directly out the engine. It looks like the (i would not say smoke although it is smokey in the exhaust way) comes directly out of the main engine where it turns right along the drivers side where some pipes begin the journey to muffler home. Is there a seal missing, a part, duct tape, anything I can do?