Zavim 3:1-2

Zavim 3:1

If a zav and a ritually clean person sat together in a boat or on a raft, or if they rode on an animal together, then even if their clothes didn’t touch, they’re (i.e., the clean person’s clothes) impure because of midras. If they sat together on a board, a bench, a bed frame or a beam when these things weren’t fastened tightly, or if they both climbed a weak tree or a weak branch on a strong tree, or an Egyptian ladder that wasn’t secured with a nail, on a bridge, a rafter or a door when not secured with clay – in all of these cases they (the ritually clean person and his clothes) are rendered unclean, though Rabbi Yehuda says that they remain clean.

Zavim 3:2

More cases: if they were both closing or opening a door. The Sages, however, say that he’s only unclean if one of them was closing and the other opening. If they were raising one another from a pit. Rabbi Yehuda, however, says this is only the case if the clean person was pulling the unclean person from the pit. If they were twisting ropes together. The Sages, however, say that’s only the case if one of them pulled one way and the other pulled the other way. If they were weaving together, whether standing or sitting, or grinding wheat. Rabbi Shimon, however, says the clean person remains clean in every case except for where they were grinding together with a hand mill. If they were unloading or loading a donkey, they are unclean if the load was heavy and clean if the load was light. All of these cases are clean for members of the synagogue (i.e., for those who eat regular, non-sanctified food) and unclean for trumah.