727 problems, opinions wanted...

Funny, I had a front pump seal leak with a new tranny and TCI converter.

What you described sounds like a drain back problem where the converter drains back into the tranny when it sits and has to refill when you put it in gear. Now, with a bad pump seal, you've got a serious drain-back, or I should say, drain out problem.

Always a good idea to replace the pump seal when you have the tranny out, despite how good it may look.

With it out, you may want to go one step further now. Drain the transmission and pull the front pump. Buy a new pump seal, o-ring, gasket, sealing washers for the bolts, and a pump bushing. You can call a place like Transmission Exchange and get everything for less than $10.

Take the front pump apart and take the pump housing, your seal, and bushing to a trans shop and have them install the parts. It'll take them 5 minutes and they probably won't charge you anything.

Put the new o-ring on the pump and reinstall it with the gasket. Lube everything up with vaseline and it'll go back together easily.

The new bushing will assure that the converter isn't wobbling and wiping out the seal. Everything else will cover most everything else that can leak from the front.

Re-adjust the bands and button it back up. You shouldn't have movement in neutral. If the problem persists you may have a valve body problem - or worse. In the end, you may be better off tearing the whole thing down for an inspection.