I had the truck at the dealer today for my 60k mi. oil change, diffs and transfer case fluid change. I also tried to get them to diagnose this strange noise that doesn't occur all the time and of course they couldn't replicate it. It's a staccato, hollow, tinny sound that happens at normal operating temps between 2000-3000 RPM when in third gear and only under load, 1/3 to 1/2 throttle application. Sometimes it doesn't happen at all. Putting the truck into 4H does not make the noise go away.
I'm thinking it's something in the trans but hard to tell.
Any ideas/suggestions?
Engine noise video #1
Engine noise video #2