I have a '97 GMC Sierra K1500 Z71 with a 4L60E transmission, and whenever it sits for a while a puddle of transmission fluid appears on the driveway underneath. It never happens while I'm around (I never actually see it drip) but it leaks pretty bad sometimes (one day when I left for work in the morning it had a 5-6" diameter puddle under it, and when I came back home it was at least triple that size). I have not been able to pinpoint where it is coming from, but I have felt around the servo, the dipstick tube, and the electrical connector on the passenger side where the puddle generally tends to form under it and everything felt dry. A friend suggested that maybe it was coming frrom the vent on top of the transmission, but what would cause fluid to come from the vent when the truck hasn't even been driven for days? Right now the truck is sitting at my mother's house until I get a major fuel leak repaired, at which time I may just get rid of it. It's been there since Mother's Day when I went to visit her (been too disgusted to look at, let alone fix my truck especially since the gas tank is full and needs to be dropped to do the repair). There is now a 2-3 foot diameter puddle of transmission fluid under it. Any ideas as to what could be causing this loss of fluid? Thanks in advance...