Bonnet and valve trim assembly and related methods are described. An example bonnet and valve trim assembly includes a bonnet structured to couple to a valve body via a valve body mounting flange, the bonnet including a cage mounting interface. A cage defining a body has a bonnet mounting interface to couple to the cage mounting interface of the bonnet. A retainer retains the cage mounting interface and the bonnet mounting interface to couple the cage and the bonnet. The retainer to enable axial movement between the cage and the bonnet when the retainer is coupled to the cage and the bonnet.