[Dean Feiock]

If it's leaking that bad on jack stands, it's possible that it's not aeration splash out the vent. Some other areas to check:

If your case is painted, soda blast the case and then dye test the area around the cooler lines for unseen cracks.

Use a depth mike to measure the pump bolt hole depth with the bell installed. A bolt that is to long may prevent to pump from sealing.

Check your front end play and compare it to your pre-teardown number. A number less than pre-teardown number would indicate something out of place which could prevent the pump from seating fully. A side note, endplay should be checked with the transmission hanging by the case. If you don't have a roll over fixture, you can mount the transmission to an engine stand. Secure the engine stand ears to the pan rail.

Remove the pump and check the gasket for cuts or tears. You should also be able to see the case impression on the gasket if the pump was seated fully.

The TA valve bodies employ the use of dual feeding the direct clutch. There should be a set screw in the reverse passage of the case, directly behind the pump. Does your new valve body also dual feed? Did the set screw need to be removed? Was a set screw installed in another passage? Is the set screw inserted far enough to be below the surface? If your new valve body uses the high gear portion of the direct clutch only, was the direct drum drilled for the venting the reverse portion of the clutch?