Well, The old adage about filling until it runs out the fill plug is just flat wrong. They all have a spec in the service manual. I filled them for years the wrong way and trust me. It's wrong. lol It always results in too high a fluid level. Every single time. I personally have never seen a vent tube from the factory in the housing in the third member area. Never. Having said that, that doesn't mean a darn thing, cause Lord knows I ain't seen it all. I'd do the relocation first and see if that fixes it. I bet it will.