'90 C1500 runs fine but very loud noise on deceleration

[OlSmokie]

Just started today. My truck takes off just fine, shifts great but when I let off the gas to come to a stop, there is a loud noise coming from under it. If I pop it into neutral while still rolling, the noise is not there.
The fluid is clean and right up and at idle there is no sound at all.
Any ideas?

 

[OlSmokie]

Update. i got under there and saw that my rear end was leaking quite a bit. I filled it up and 90% of the noise went away.

 

[Justin S]

Well there ya go, rear bearings.