4 Wheel Drive Noise

[Weiant2001]

94 K1500
165K miles

While in 4 high, between 40-55 mph, when I left off the gas it makes a noise like an low level engine brake. but only when i have no gas pedal input. When there is a little input, the noise goes away?

Is this normal? Or is there a contributing factor I should look at before it gets worse? I haven't had a chance change all the fluids yet. I did have the CV axles replaced when I had the lift put on.

I appreciate any insight.

 

[Schurkey]

Fluid condition, and fluid level in the front differential and the transfer case?

How long has it been since you checked/greased the front driveshaft?