it doesn't leak at all when it runs, but after I parked the car, like 1h after, there was a pudle. Would overfiling the trany creates this problem?? I can't figure it out...and absulotly no driping when it's running/driving. weird! help! thanks

Sounds like a drainback condition is showing up a leak that isn't there when running since the oil level will be lower than that. Check something obvious like the dipstick tube.

What else should I check? it's not the dipstick, and only the X-member under the trans bushing is wet....