My unit is in the garage,vertical, accessible, with drain line running outside. Water is seeping from under the unit. I have cleaned the drain. Does the Trane unit have a drain pan inside that is possibly clogged and overflowing? I cannot see where the water is coming from.Can I gain access to the pan by removing the metal panel that covers the coil? Any help would be greatly appreciated

Yes it does have a pan and if you try you may be able to get to it but you may not be able to see all that you need to. Depending on the age of your unit it can have a metal pan or a plastic pan. Not as much trouble with the plastic, lots of trouble with the metal pans because of rust flakes getting into the small passages that the water drain through. A notorious for stopping up os right where the drain line connects to the coil pan.