motor 112 not shown secured to the mounting 196 is then fitted onto the main body 111 by placing each locating post 154 into its corresponding hollow holding tube 156 simultaneously as shown in fig4 a each welding ring 184 on the cover 134 will fit into the space between its corresponding welding pad 172 and short tube 174 shown in fig3 b likewise each locating rib 186 in fig4 a will snap into its corresponding acoustical chamber 180 in fig3 b with reference to fig2 a when the cover 134 is secured by ultrasonic welding onto the main body 111 the output gear 140 will be retained on the output shaft 142 between the first collar 144 of the main body 111 and the second collar 146 of the cover 134 thus the first collar 144 retains the output gear 140 on one side while the second collar 146 retains the output gear 140 on an opposite side because the d c motor 112 is secured onto the cover 134 instead of onto the main body 111 the entire drive assembly inside the gear box 110 can be fully tested prior to sealing by ultrasonic welding of the cover 134.