Which side of the suction tube goes towards the pump and which one goes towards the casting? I installed it the same way it was when I replaced the pump but I"m thinking it may have been in wrong. I"m sucking lots of air and can"t imagine it being in backwards would allow that much air to be sucked in. The o-ring in the pump seems fine but I"m replacing it this time around. What"s the best way to re-assemble? Mount it in the casting and slide the pump in or mount it in the pump and slide the pump in? Other than the large o-ring between the rear end that I replaced when I put a new TA section in where else can it be sucking air from? I intentionally filled the hy-tran level 2-3 inches higher. It helped but it still sucked air. I am using an industrial model filter with casting spacer too.