I had a problem with my M1009 not shifting and after replacing all the hoses I did find out that it was the metal vacuum pipe. The TM listed the part number as #15599235 and it seems GM no longer makes this and NAPA does not seem to have it. I also called O'reilly's and they cannot find it. Anyone know where to get one? Right now I am using a rubber vacuum hose in it's place. I did read a thread here a while ago about someone suggesting a brake line but I cannot find that thread for the life of me. Any suggestions would be helpful.