A new modular gear drive is a design improvement and significant expansion for the Rotomixx sanitary mixer. The change accommodates larger motors than the previous design and is available in several speed ratios, which optimize mixer sizing for better process results. The Rotomixx frame has a new modular gear drive assembly that attaches directly to the direct drive bearing frame, which supports longer shafts and higher torque loads. The design change also enables the manufacturer to lower its manufacturing costs and pass those savings on to customers and to substantially reduce lead times.