I have a 2003 4x4 Sonoma. I have read through here about the Transfer Case filling up with ATF and contaminating the Vacuum lines. I want to replace the vacuum lines because of the ATF contamination and the dry rotting. The problem is this is my DD and I can't just take it apart. I was hoping someone knew the sizes of the lines in the system so I can order replacement ones. I am thinking of using silicone vacuum lines from a place like Silicone Intakes.

Thanks guys. Hopefully this first post is a good one.

 

Welcome to the forum! Go blue!

Fix the problem before you replace the lines. Transfer case input shaft seal, and possibly the vacuum switch, (if equipped). There are a couple of different sizes used, but most of the lines under the hood are 5/32". Clip off an inch or so off the end and take them to the parts store, match 'em up. The aftermarket replacement line is better quality and it should be fine. The HVAC lines in the dash are more of a plastic type material, and smaller diameter.

 

I was planning on doing it all in one job. I totally agree with fixing the transfer case stuff first. It makes no sense to fix something that isn't the root source of the problem. I already bought the seal and switch. Sorry that I wasn't clear on that. I just figured while I am in there changing stuff to replace the lines as well. Hence the question. The main reason I asked is because I wanted to know if by chance the vacuum switch fails again would the ATF eat up the silicone vacuum lines I am looking at? Also, since this is a pretty common issue I was also hoping someone would chime in with the info of the line sizes so I could order them.

These are the lines I am talking about:
siliconeintakes.com boost/vacuum hose