Did a search and only found two threads...one reply was 1/4" and the other was 4 mm (for a 2004). I've read that some members will change a straight fitting to an angled one in order to get at difficult fittings.

I have a 2003 GMC...anyone confirm if it's 1/4" or 4 mm? planning on doing my own chassis lube and since I'll be under there, I figure I might as well change any difficult to access fittings at the same time.

Thanks in advance.

They're 1/4-28 std fittings

Thanks, btfarm.