Not really a question or issue with my truck - just a thought I had concerning motor oils. When my mechanic changed out my timing chain cover gasket, he also checked out my oil pan gasket since the two are related in that the TC cover sits on top of the front of the oil pan. He said it was not a problem since the oil pan gasket on my truck is a one piece metal type gasket but he did say that when he took the pan off he was pleasantly surprised to see that the crank and journal bearings looked like they were brand new. He even took readings with plastic gauge on one of the journal bearings and that they showed absolutely no wear. My '96 has 115,000 on it and I have always changed the oil every 3,000 miles and currently use Valvoline high milage oil. My thing is about 5 years ago I attended a training session that was offered at work. At the time I was working as a systems mechanic at a power plant where i rebuilt compressors and pumps. This training was on lubrications and the instructor told us that tests have been done on many different types of motor oils and that in reality - one does not really have to change out their oil till about 6,000 miles. This is when tests have shown that the viscosity really starts to break down. Synthetics can last even longer. He said that the problem is the cleanliness of the oil which can be solved just by changing out the filter. He and I kind of got into a friendly argument in that i told him that for the cost of changing out the filter - you might as well just change the oil. He agreed and he said he was just making the statement in that todays oils can last longer than the 3,000 miles that we all use as the benchmark to change. What does everyone think about this and also what luck have you had with the different oils you use - synthetic or conventional. My mechanic told me that he rarely sees a motor crank as clean and shiney as mine. I'll stick with the Valvoline High milage every 3000 miles.