Shaking rear end

[sntrym]

I've had this exact issue with a couple different trucks due to out of round drums or the balance weight falling off. If the drums were stored or shipped on their sides, they will go slightly out of round and cause this. I've had good luck with Napa drums only. Other brands are hit and miss. I would suggest having the axles checked by a shop to make sure they are in the tolerance range. Have the drums checked as well and replace them (and have those checked) if needed.