[KYDeepwater]

I have access to an oil analysis company through work, so I have been testing Mobil 1 versus the supertech from Wal-mart. The Mobil 1 seems to have some visual advantages, it wasn't cloudy like the Supertech after 7,500 miles, but the wear metals were virtually the same. I have had around 100 ppm iron in the oil each test since 15,000 miles. I plan on now going to use the Mobil 1 75W140 for 15,000 miles to see if anything in the oil testing changes. I figure it is worth $30.00 to change it since there has been a lot of concern over these rear ends. From what I have seen here, most of the problems with the diff's have been the locking rear diff's, but there were some regular ones that failed. I have had the PML aluminum cover on since last May; this past weekend we pulled the boat 140 miles from the lake to the house, and I could place my hand of the cover when we got home without it being too hot.
The manual recommends 5W30 for our engine. I would try that and see if it improves the ticking.