4 speed leaking rear seal??

Well before you call, then prove you didn't dislodge the gator-spring with your tapping. If you did, then you can bend a coat-hanger wire and reinstall it without removing it. IF you replace that seal, put some grease on that spring to prevent that. I have, in the past, successfully removed that rear seal without damaging it, but I fabbed up a curved spoon to do it. Once out, you can fit it to the yoke and see what's going on.If you damaged the seal during the install, it will be leaking from the outside perimeter. If it leaks from inside the boot and comes out the weephole at the top,or from the yoke-interface, then IDK; it looks like a mismatch of parts.

Some older style of yokes had a weephole in an expansion-plug, installed on the end of the front yoke,altho I think that was GMs.
And as always, make sure you didn't overfill it; there shouldn't be any oil back there other than splash....unless....... you can leave, wheels-up!,lol.