Where is the supply side auto transmission line located on a 2005 GMC envoy XL SLE
You mean transmission cooler line?
I am wondering why you ask. If you are having trouble with it, read up on it from owners at http://www.carproblemzoo.com/gmc/envoy/automatic-transmission-cooler-problems.php
Looking for a Used Envoy in your area?
CarGurus has 2,299 nationwide Envoy listings starting at $895.
Search GMC Envoy Questions
Are you a UK consumer? CarGurus now has a discussion forum in the UK.
GMC Envoy Experts