Rear end shake upon acceleration

[Nathanf44HH]

I have 79 gmc heavy half .I was driving it today and I noticed a squealing noise and soon after felt a slight grinding noise coming from the back end .It gets worse on eccelleration .when I let off the throttle it becomes smoother and the noise stops . I jacked it up and checked the rear pumpkin and it has clean full fluid .the axels have a little play but not excessive amount .Has anyone had this issue ?

 

[Tank6x2]

Centre shaft support bearing or mud/snow or ice caked on the inside of the rim, beyond that check your universal joints while your there…

 

[1973c10]

Welcome aboard

check the U joints