vibrating/bumping in rear wheels, what is causing the problem
I would say that you have at least one tire out of balance. Its usually about 8-10 dollars to balance a tire at most shops.
aside from wheel balancing; bent or damaged rim, or a separated tire.
As mentioned above a bad tire or rim is possible,but if the problem presists you might have to have the drive shaft balanced.
Looking for a Used Silverado 1500 in your area?
CarGurus has 196,395 nationwide Silverado 1500 listings starting at $699.
Search Chevrolet Silverado 1500 Questions
Chevrolet Silverado 1500 Experts
Related Models For Sale
Used Cars For Sale