This has only been happening the last week or so. We just moved into an older home and had central A/c Installed. Installer said the drain pipe on our washer must of came loose and the water was draining out under the house. So he just put the 2 pieces back together. Ever since then Im getting the gurggling sound in the sinks when the washer drains. We only have 1 bath and the toilet doesn't seem affected. But I checked the pipe outside and ran a snake in it to see if it was clogged. But didn't hit any obstructions. Had someone stay inside and flush some TP in the toilet, ran hot water in the kitchen sink(never went by) Ran some water in the pipe outside with the hose and it drained away from the house fine. We have the kitchen on one side of the house and the washer and bath on the other side. So I know we have a clog. Could we put draino in each of the sinks and down the washer pipe? Or what else should we try. I don't know what a roof vent pipe is. How do I locate it?

Oh and smell the sewage gas outside by the pipe I checked

Could we put draino in each of the sinks and down the washer pipe? I am no fan of putting harsh chemicals in your drainage system. Besides, they only seem to work in TV ads.
You're snaking the wrong pipes. Snake both the washer and the kitchen sink roof vents and see if that doesn't help. Good
I don't know what a roof vent pipe is A roof vent pipe is the pipes that stick out of your roof. Every fixture that has a trap MUST be vented by code. Good luck, Tom