I had previously replaced the pump about 1 year ago. That was not the problem. Still leaked the same way - intermittently, but always in the center of the washer onto the floor. None of the hoses were leaking - no evidence of corrosion or water mineral residue at any of the hose fittings. So, it must have been something else. I studied the parts diagram for the washer tub assembly and concluded the source of the leak almost had to be the outer tub's Centerpost Gasket. It was really the only part left that came in direct contact with water in the otherwise sealed outer tub.
Gonna backtrack a little here... When I was checking for leaks before and after I swapped out the pump (about 1-1/2 years ago), I noticed the rear lower frame of the machine was almost totally rusted out and the Suspension Spring was was about to rust through also. I had some 2" angle aluminum in my garage, so I cut a section of that about the width of the machine and pop-riveted it to the machine back panel with the angle facing inward. That did the trick and completely reinforced that lower section of the washer. It also gave me solid metal to drill a new hole for the suspension spring. The point here is not the innovative repair - the point is that the machine had been leaking for a long time and rusted out the lower rear frame and suspension spring! (The actual visible water on the concrete floor only manifested itself about a year and a half ago, but based on the extensive rust, it had to have been leaking much longer than that.)
Back to fixing the leak...I ordered the parts from Appliance Parts Pros. (I rebuilt the agitator section too, with a new Medium Cam Agitator Repair Kit. This had nothing to do with the leak, but since I was taking the whole thing apart anyway...) The main components I ordered for the leak were the Centerpost Gasket and Spanner Wrench. I also ordered a new Suspension Spring because the old one was just about rusted through.
I followed some instructional videos on how to remove the inner basket from the outer tub. The spanner wrench was an absolute necessity. Once I got the inner tub out, I removed the old style filter on the bottom of the inner tub and cleaned it up thoroughly. (I replaced the old style filter with the new Washer Filter Plug Kit - four small plastic filters that fit in the four large holes in the inner tub. The holes were a little too large for the plugs to stay snug, so I super-glued them in.)
I then removed the outer tub by sliding it up the centerpost. Cleaned it up thoroughly also. That's when I noticed the triangular frame to which the motor/transmission assembly was attached was rusting severely at each of its three corners. One corner had rusted through. This is evidence of a Centerpost Gasket leak, as all this rust was above the water pump.
In order to curtail any more rusting on the triangular frame, I knocked out all of the loose rust and scrapped the rest of it to remove as much rust as possible. In each of the three corners, there is a downward-facing "bowl" in the metal frame where the support posts extend upward. These "bowls" had been collecting water for years, hence the extensive rust. To combat the rust and prevent any further rust I heated up the hot glue gun and I must have used (5) 12-inch sticks of hot glue to fill in the bowls, cover up all the rust, and actually made them convex so water will run outward and not get trapped if it ever leaks again. Whew!
I then used 0000 steel wool on the centerpost to remove some minor corrosion so the new gasket would seal. I placed a small amount of silicon grease on the centerpost where the gasket will seat. I then pressed the new gasket into the outer tub and applied silicon grease on the inside so it would slide into place without sticking on the way down (about 12 inches). I seated the tub and secured it. I installed the new Suspension Spring. I reinstalled the inner tub and cinched it down snugly with the spanner wrench. Reinstalled the newly rebuilt agitator and snugged down its retaining bolt. Reinstalled the washer body and set the spring clips. Hooked up the water and drain line and crossed my fingers.
My wife did laundry the next day. No leaks. It's now been right at a month and many laundry loads later...no leaks!!! Yay! Project took me about 5 hours including the hot gluing and extreme cleaning of all the parts.