That would be nice, except I change the fluid yearly. I drive the truck a little hard.
I was staying out of this, because in over 200K on my old 9 inch, I don't ever remember having a leak from the third member gasket. No idea what was used.
But then I read where you change fluids yearly, and a thought occurred. As I have mentioned here before, I usually have to change all the fluids in my truck after every hunting season to get the water out.
My old 9 inch was a pain, but I built a suction device with a semi-rigid tube that would slip in the fill hole and suck all the water and old fluid out.
Then one day, I discovered why I had had a leak where the axle tube entered the third member housing ever since it was new.
Ford had issued a recall or warning for bad welds at that point. The weld was fine, but the welder missed and put all but just a small piece on the tube and almost none on the housing.
The dealer was supposed to inspect the weld and either replace the rear end or have it re-welded.
Mine did neither. They just smeared some black RTV sealer on the seam. I slid under to check my U-Joints after the warranty ran out, and the tube had slid about 1/4 inch out of the housing!!
I drove it back in, and
carefully drove it to a machine shop I knew.
Don't worry, I am going somewhere with this.............
We pulled the axle shafts, and the third member. Then we carefully aligned the original weld points, and re-welded the tube correctly.
Then we turned it over, and ground the flat place on the bottom of the housing off smooth.
Took a piece of 1/2 inch plate, the size of that place and beveled one side of it all the way around.
Placed it on the flat part of the housing with the beveled side toward the housing so it created a tapered gap.
Clamped it down, and welded up the gap all the way around. Then ground an outside bevel through the outside of the weld, so that the plate would slide over any stumps or logs.
Also inspected the weld to make sure there were no gaps or pores. Then we drilled the center of the plate, all the way through the housing, and tapped it for a 1/2 NPT fitting. Found an Allen head flush plug that fit and screwed it in with some Teflon tape.
After that, year end lube changes became a lot easier. Just use a big Allen head wrench to remove the plug and let the lube and water drain out.
With all the work you seem to have done already to the rear end, its a crime not to add a drain plug............
I do recommend the reinforcement plate. I was just too nervous about drilling and threading the housing by its self.