www.myhvacparts.com I have used these guys for TRANE parts before. Always have trouble with Trane, they are a bit tight lipped about service manuals, and are right proud of the parts, if you go to an authorized dealer. Replace the cap. again when you...
(800) 940-1344 between 7:30 a.m. and 4:30 p.m. CT Monday through Friday
Bryant is a lot cheaper and actually made by trane, had my central a/c replaced earlier this year and Trane wanted to charge me 10K. Had someone else install a bryant for about 3K less