The bearing kit comes with the bearings, seals and the bushing as you can see in the picture below.
The tcase chain will stretch over time and will need to be replaced. The most common symptom is a knocking sound or a clacking noise when you take off from a dead stop. For example, you are at a stop light and when the light changes you speed up and the noise happens. The stretched chain is skipping over the sprockets. If not fixed the sprockets can wear down and as a result will need to be replaced too.