I had the same thing on my 4L30E , and its not a 2 hour job , my mechanic fixed it in about 30 minutes , all he replaced was a seal under it.

is yours metal or rubber for that round piece? Mine was metal so not sure if that makes a big difference or not.

1996 Jeep Grand Cherokee 5.2 with mods.Hughes Air gap intake , 52MM TB , ford injectors, 2 3/4" lift, Doug Thorley headers , HID headlights with LED , HID fog lights , glow gauges , a few others