Whether considered "metal" or not, the ending of the track "A Song For The Deaf" by QOTSA morphs from jagged guitar riffs to a horn section playing the same atonal figure at the end of the song. There are also saxophone solos and other horn parts scattered among their other releases.
You can blame me if you want (joking). Josh Homme used to shop at the used CD store I managed in Seattle, he came in once looking for suggestions on John Coltrane and Charles Mingus CDs, so I took him around the store and helped him pick out several. This was prior to their debut album coming out. I still have a signed copy of the Kyuss Into The Void single that he brought in as a thank you for helping out with picking jazz CDs.