I have OLM in my 03 Avalanche also. I let it go to zero everytime and it varies between 4800- 5200 miles. I now have 39000 on it and have not had any problems. I used to do every 3000, but now usually do 5000 on my other cars. My neighbor has a 90 Dodge pickup he bought new, it has 226000 on it and has never changed the oil only added when low and it runs good and doesn't smoke. I think oil can go a lot longer then we think it can.
