I was wondering if anyone has been running any oil from Amsoil... if so what are you using? Fully synthetic blend? How often are you changing it out?

Yes, I'm running their 15W-40 HD Marine & Diesel oil (AME (http://www.amsoil.com/storefront/ame.aspx)).

I am changing it out as per oil analysis. Since I've been seeing high copper numbers, I have been changing the oil & filter at 5,000 to 8,000 miles. Copper has been dropping steadily since new.

After I install a by-pass oil filter system I should be able to safely go beyond 10,000 miles between oil changes.

I just put it on our 06 LLY. I've run the stuff for years.

Looks like the bi-weekly amsoil add

I only run the best also,amsoil 15/40 ame.

I run 5w-30 heavy duty diesel amsoil,and haven't melted any bearings yet. Oil sample twice a year,change at 12000 mi. or once a year, unless oil sample states otherwise.

On the LBZ, the oil should be good to go. On the tranny, you have Dex-VI in there now... best to hold off until it's verified that the synthetic Dex-III's are good enough. Theoretically, they should be, but the Dex-VI does appear to be superior to Transynd.