New noise...

So a recently new noise. Seems to be coming from under the truck towards the middle.

Happens regardless of what gear I am in. It gets a little more intense with higher speed.

Only happens when in motion and in gear.

When I am coasting in neutral say down a hill or up to a stop light then it seems to instantly go away the moment I go out of gear into neutral.

Thoughts?

 

If the noise changes with speed and happens when in motion then it has to be somewhere in the driveline. I'd start by looking at U joints and carrier bearing. Do you grease your joints regularly (or are yours even the greasable variety?), does the carrier bearing have slop, does your truck have lots of miles and maybe the U joints have never been replaced aka there are no needles left inside? Those are the simple things. Check to make sure your transfer case has proper fluid level. Check for leaks at transmission or anything loose or weird going on in that area.

 

Got a Video....

 

All good questions. U joints have 38 thousand miles on them and appear to be in good shape. Carrier bearing also has 38 thousand miles on it.

Transmission gear oil appears to be right at or slightly below the fill plug. Diff gear oil level is good as well.