I can't remember where the strainer was but behind the rear seat back there is a plastic cap in the bulk head pop that off and remove the big nut and you can pull up the gauge tube etc. I also at the same time removed the fittings from the bottom of the tank but I don't remember where the strainer is, but I do remember it was fairly course screen. I had a bad case of algae in an 84 SD and the sreen was not plugged up but the tube for the gauge was all gunked up, there is a little hole at the bottom of it that needs to be cleaned.