Robot model falls down in Gazebo when setting <transmission> as EffortJointInterface

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Robot model collapses in Gazebo when setting <transmission> as EffortJointInterface. How to fix this? Any advice will be appreciated.

And below's the content of the urdf file

<!-- This URDF was automatically created by SolidWorks to URDF Exporter! Originally created by Stephen Brawner (brawner@gmail.com) 
     Commit Version: 1.6.0-1-g15f4949  Build Version: 1.6.7594.29634
     For more information, please see http://wiki.ros.org/sw_urdf_exporter -->

<robot name="arm">

  <link name="world" />

  <link name="base_link">
    <visual>
      <origin xyz="0 0 0" rpy="0 0 0" />
      <geometry>
        <mesh filename="package://arm_description/meshes/base_link.STL" />
      </geometry>
      <material name="3143">
        <color rgba="0.79216 0.81961 0.93333 1" />
      </material>
    </visual>
    <collision>
      <origin xyz="0 0 0" rpy="0 0 0" />
      <geometry>
        <mesh filename="package://arm_description/meshes/base_link.STL" />
      </geometry>
    </collision>
    <inertial>
      <origin xyz="-0.52E-03 -0.01E-03 20.01E-03" rpy="0 0 0" />
      <mass value="1.25" />
      <inertia ixx="3000.53E-06"    ixy="-2.36E-06"    ixz="-15.68E-06"
                                    iyy="3039.39E-06"  iyz="0.05E-06"
                                                       izz="5609.85E-06" />
    </inertial>
  </link>

  <joint name="joint_0" type="fixed">
    <origin xyz="0 0 0" rpy="0 0 0" />
    <parent link="world" />
    <child link="base_link" />
  </joint>

  <link name="J1_link">
    <visual>
      <origin xyz="0 0 0" rpy="0 0 0" />
      <geometry>
        <mesh filename="package://arm_description/meshes/J1_link.STL" />
      </geometry>
      <material name="">
        <color rgba="1 1 1 1" />
      </material>
    </visual>
    <collision>
      <origin xyz="0 0 0" rpy="0 0 0" />
      <geometry>
        <mesh filename="package://arm_description/meshes/J1_link.STL" />
      </geometry>
    </collision>
    <inertial>
      <origin xyz="-2.92E-03 0.04E-03 -68.53E-03" rpy="0 0 0" />
      <mass value="8.62" />
      <inertia ixx="31417.22E-06"    ixy="-7.17E-06"    ixz="1741.59E-06"
                                     iyy="31776.39E-06" iyz="-13.11E-06"
                                                        izz="13349.46E-06" />
    </inertial>
  </link>

  <joint name="J1_joint" type="revolute">
    <origin xyz="0 0 0.141" rpy="0 0 0" />
    <parent link="base_link" />
    <child link="J1_link" />
    <axis xyz="0 0 1" />
    <limit lower="-3.1416" upper="3.1416" effort="200" velocity="6.1416" />
    <dynamics D="1" K="7000" damping="0.003" friction="0.0" mu_coulomb="0" mu_viscous="16"/>
    <safety_controller k_position="200.0" k_velocity="200.0" soft_lower_limit="-3.6" soft_upper_limit="3.6"/>
  </joint>

  <link name="J2_Link">
    <visual>
      <origin xyz="0 0 0" rpy="0 0 0" />
      <geometry>
        <mesh filename="package://arm_description/meshes/J2_Link.STL" />
      </geometry>
      <material name="">
        <color rgba="0.792156862745098 0.819607843137255 0.933333333333333 1" />
      </material>
    </visual>
    <collision>
      <origin xyz="0 0 0" rpy="0 0 0" />
      <geometry>
        <mesh filename="package://arm_description/meshes/J2_Link.STL" />
      </geometry>
    </collision>
    <inertial>
      <origin xyz="-200.85E-03 0 132.08E-03" rpy="0 0 0" />
      <mass value="14.09" />
      <inertia ixx="43424.6E-06"   ixy="-17.37E-06"       ixz="-52659.14E-06"
                                   iyy="1117037.51E-06"   iyz="-9.59E-06"
                                                          izz="1093506 ...