vibrations?

[jks67ss396]

Hey guys

Im trying to see if i have an issue with my 5.3/4l60 or not

this doesnt happen if the truck is in park and i just rev the engine, so i dont think its engine

When driving the truck, there seems to be a certain resonant frequency/rpm that i feel slightly through the dbw pedal when i get on it a little. its probably the whole truck, but i feel it more in the pedal instead of the carpeted floor.

its not so much of "uh oh, something is wrong" as more of a "hey this thing has some b@lls"

if i let off the gas, the slight vibration goes away, get back on it, it comes back.

but as i gain speed, it goes away

its a 2 piece driveshaft

Ive checked motor mounts, trans mounts, ujoint strap bolts, greased all ujoints, checked exhaust bolts (have those layered rubber isolator hanger straps)

trans fluid is new, new filter, correct fluid level, external cooler

is this something on trans? something with 2 piece shaft? normal?

i would expect this kinda vibration through a throttle rod connected big block or if i have a misadjusted throwout bearing on a mechanical clutch, but not a dbw 5.3

thoughts? or your own experiences?

thanks guys!