Heater Core Help

[GeneP]

Did a search here & got some info but would like more input.
Wife's 97 GMC Jimmy, for several months its been leaving spots in the driveway been drivin me crazy figuring out where its coming from. Last couple weeks they're getting bigger. Directly under tranny but not tranny fluid. By the way the actual heat it puts out sux. Crawled under it today and found drops of antifreeze hanging from shifter linkage on tranny. Just above that is a 1/4" rubber line cut off at a 45 Degree angle. Is this a vent or drain line for the heater core box that is the source? If not what is it? 2nd to replace the heater core the Chiltons I have ain't much help. Do I need to remove the dash? Or what sequence to I start takin stuff apart to get to it. Thinking the problem might be the heater core leaking but the floor is dry. Any & all recommendations would be greatly appreciated.

Gene

[blazee]

One thread is enough. Don't start identical threads in multiple forums.