Hello Eitan,

I am running an AMCL (diff drive) in which parameters are:
  <param name="odom_frame_id" value="/odom"/>
  <param name="base_frame_id" value="/base_link"/>
  <param name="global_frame_id" value="map"/>

In my global costmap conf: 
global_costmap:
  global_frame: /map
  robot_base_frame: base_link

and in LocalCostMap conf:
  global_frame: odom
  robot_base_frame: base_link

and in odom TransformStamped message settings:
  geometry_msgs::TransformStamped odom_trans;
  odom_trans.header.frame_id = "odom";
  odom_trans.child_frame_id = "base_link";

The link is: /map->/odom->/base_link->/base_laser_link

As i said initially it works nicely but after some period it falls off.

My simulation real time parameter is set to false. If i make it true the 
navigation stack hangs.
<param name="use_sim_time" value="false"/>

Please let me know if i need to sync. frequency.

- Prasad Dixit