diff --git a/lib/mongo/repl_set_connection.rb b/lib/mongo/repl_set_connection.rb
index 059e0f5..7505bdf 100644
--- a/lib/mongo/repl_set_connection.rb
+++ b/lib/mongo/repl_set_connection.rb
@@ -114,6 +114,7 @@ module Mongo
 
       # No connection manager by default.
       @manager = nil
+      @old_managers = []
 
       # Lock for request ids.
       @id_lock = Mutex.new
@@ -125,6 +126,7 @@ module Mongo
       @safe_mutexes = Hash.new {|hash, key| hash[key] = Mutex.new}
 
       @connect_mutex = Mutex.new
+      @refresh_mutex = Mutex.new
 
       check_opts(opts)
       setup(opts)
@@ -147,14 +149,15 @@ module Mongo
 
         discovered_seeds = @manager ? @manager.seeds : []
         @manager = PoolManager.new(self, discovered_seeds)
+        Thread.current[:manager] = @manager
 
         @manager.connect
         @refresh_version += 1
 
-        if @require_primary && self.primary.nil? #TODO: in v2.0, we'll let this be optional and do a lazy connect.
+        if @require_primary && @manager.primary.nil? #TODO: in v2.0, we'll let this be optional and do a lazy connect.
           close
           raise ConnectionFailure, "Failed to connect to primary node."
-        elsif self.read_pool.nil?
+        elsif @manager.read_pool.nil?
           close
           raise ConnectionFailure, "Failed to connect to any node."
         else
@@ -196,19 +199,19 @@ module Mongo
     def hard_refresh!
       log(:info, "Initiating hard refresh...")
       discovered_seeds = @manager ? @manager.seeds : []
-      background_manager = PoolManager.new(self, discovered_seeds | @seeds)
-      background_manager.connect
+      new_manager = PoolManager.new(self, discovered_seeds | @seeds)
+      new_manager.connect 
 
       # TODO: make sure that connect has succeeded
-      old_manager = @manager
-      @manager = background_manager
-      old_manager.close(:soft => true)
+      @old_managers << @manager
+      @manager = new_manager
+
       @refresh_version += 1
       return true
     end
 
     def connected?
-      @connected && (self.primary_pool || self.read_pool)
+      @connected && (@manager.primary_pool || @manager.read_pool)
     end
 
     # @deprecated
@@ -221,14 +224,14 @@ module Mongo
     #
     # @return [String]
     def host
-      self.primary_pool.host
+      @manager.primary_pool.host
     end
 
     # The replica set primary's port.
     #
     # @return [Integer]
     def port
-      self.primary_pool.port
+      @manager.primary_pool.port
     end
 
     def nodes
@@ -242,7 +245,7 @@ module Mongo
     #
     # @return [Boolean]
     def read_primary?
-      self.read_pool == self.primary_pool
+      @manager.read_pool == @manager.primary_pool
     end
     alias :primary? :read_primary?
 
@@ -294,96 +297,68 @@ module Mongo
       end
     end
 
+    # Generic socket checkout
+    # Takes a block that returns a socket from pool
+    def checkout(&block)
+      if connected?
+        sync_refresh
+      else
+        connect
+      end
+      
+      begin
+        socket = block.call
+      rescue => ex
+        checkin(socket) if socket
+        raise ex
+      end
+      
+      if socket
+        socket
+      else
+        @connected = false
+        raise ConnectionFailure.new("Could not checkout a socket")
+      end
+    end
+    
     # Checkout a socket for reading (i.e., a secondary node).
     # Note that @read_pool might point to the primary pool
     # if no read pool has been defined.
     def checkout_reader
-      if connected?
-        sync_refresh
-      else
-        connect
-      end
-      begin
-        socket = get_socket_from_pool(self.read_pool)
+      checkout do
+        socket = get_socket_from_pool(:read)
         if !socket
           connect
-          socket = get_socket_from_pool(self.primary_pool)
+          socket = get_socket_from_pool(:primary)
         end
-      rescue => ex
-        checkin(socket) if socket
-        raise ex
-      end
-
-      if socket
         socket
-      else
-        @connected = false
-        raise ConnectionFailure.new("Could not connect to a node for reading.")
       end
     end
 
+    # Checkout a socket from a secondary
+    # For :read_preference => :secondary_only
     def checkout_secondary
-      if connected?
-        sync_refresh
-      else
-        connect
-      end
-      begin
-        socket = get_socket_from_pool(self.secondary_pool)
-      rescue => ex
-        checkin(socket) if socket
-        raise ex
-      end
-
-      if socket
-        socket
-      else
-        @connected = false
-        raise ConnectionFailure.new("Could not connect to a secondary for reading.")
+      checkout do
+        get_socket_from_pool(:secondary)
       end
     end
 
     # Checkout a socket for writing (i.e., a primary node).
     def checkout_writer
-      if connected?
-        sync_refresh
-      else
-        connect
-      end
-      begin
-        socket = get_socket_from_pool(self.primary_pool)
-
-        if !socket
-          connect
-          socket = get_socket_from_pool(self.primary_pool)
-        end
-      rescue => ex
-        checkin(socket)
-        raise ex
-      end
-
-      if socket
-        socket
-      else
-        @connected = false
-        raise ConnectionFailure.new("Could not connect to primary node.")
+      checkout do
+        get_socket_from_pool(:primary)
       end
     end
 
     # Checkin a socket used for reading.
     def checkin_reader(socket)
-      if !((self.read_pool && self.read_pool.checkin(socket)) ||
-        (self.primary_pool && self.primary_pool.checkin(socket)))
-        close_socket(socket)
-      end
+      socket.pool.checkin(socket)
       sync_refresh
     end
 
     # Checkin a socket used for writing.
     def checkin_writer(socket)
-      if !self.primary_pool || !self.primary_pool.checkin(socket)
-        close_socket(socket)
-      end
+      socket.pool.checkin(socket)
       sync_refresh
     end
 
@@ -395,7 +370,20 @@ module Mongo
       end
     end
 
-    def get_socket_from_pool(pool)
+    def get_socket_from_pool(pool_type)
+      if Thread.current[:manager] != @manager
+        Thread.current[:manager] = @manager
+      end
+
+      pool = case pool_type
+        when :primary
+          primary_pool
+        when :secondary
+          secondary_pool
+        when :read
+          read_pool
+      end
+
       begin
         if pool
           socket = pool.checkout
@@ -406,47 +394,51 @@ module Mongo
         return nil
       end
     end
+    
+    def local_manager
+      Thread.current[:manager]
+    end
 
     def arbiters
-      @manager.arbiters.nil? ? [] : @manager.arbiters
+      local_manager.arbiters.nil? ? [] : local_manager.arbiters
     end
 
     def primary
-      @manager ? @manager.primary : nil
+      local_manager ? local_manager.primary : nil
     end
 
     # Note: might want to freeze these after connecting.
     def secondaries
-      @manager ? @manager.secondaries : []
+      local_manager ? local_manager.secondaries : []
     end
 
     def hosts
-      @manager ? @manager.hosts : []
+      local_manager ? local_manager.hosts : []
     end
 
     def primary_pool
-      @manager ? @manager.primary_pool : nil
+      local_manager ? local_manager.primary_pool : nil
     end
 
     def read_pool
-      @manager ? @manager.read_pool : nil
+      local_manager ? local_manager.read_pool : nil
     end
 
     def secondary_pool
-      @manager ? @manager.secondary_pool : nil
+      local_manager ? local_manager.secondary_pool : nil
     end
 
     def secondary_pools
-      @manager ? @manager.secondary_pools : []
+      local_manager ? local_manager.secondary_pools : []
     end
 
     def tag_map
-      @manager ? @manager.tag_map : {}
+      local_manager ? local_manager.tag_map : {}
     end
 
     def max_bson_size
-      if @manager && @manager.max_bson_size
-        @manager.max_bson_size
+      if local_manager && local_manager.max_bson_size
+        local_manager.max_bson_size
       else
         Mongo::DEFAULT_MAX_BSON_SIZE
       end
@@ -513,12 +505,32 @@ module Mongo
       raise NodeWithTagsNotFound,
         "Could not find a connection tagged with #{tags}."
     end
+    
+    def prune_managers
+      @old_managers.each do |manager|
+        if manager != @manager
+          if manager.closed?
+            @old_managers.delete(manager)
+          else
+            manager.close(:soft => true)
+          end
+        end
+      end
+    end
 
     def sync_refresh
       if @refresh_mode == :sync &&
         ((Time.now - @last_refresh) > @refresh_interval)
         @last_refresh = Time.now
-        refresh
+        
+        if @refresh_mutex.try_lock
+          begin
+            prune_managers
+            refresh
+          ensure
+            @refresh_mutex.unlock
+          end
+        end
       end
     end
   end
diff --git a/lib/mongo/util/pool.rb b/lib/mongo/util/pool.rb
index f04a705..2d77489 100644
--- a/lib/mongo/util/pool.rb
+++ b/lib/mongo/util/pool.rb
@@ -65,22 +65,12 @@ module Mongo
     #   close only those sockets that are not checked out.
     def close(opts={})
       @connection_mutex.synchronize do
-        if opts[:soft]
-          sockets_to_close = @sockets - @checked_out
+        if opts[:soft] && !@checked_out.empty?
+          close_sockets(@sockets - @checked_out)
         else
-          sockets_to_close = @sockets
+          close_sockets(@sockets)
+          @closed = true
         end
-        sockets_to_close.each do |sock|
-          begin
-            sock.close unless sock.closed?
-          rescue IOError => ex
-            warn "IOError when attempting to close socket connected to #{@host}:#{@port}: #{ex.inspect}"
-          end
-        end
-        @sockets.clear
-        @pids.clear
-        @checked_out.clear
-        @closed = true
       end
     end
 
@@ -256,9 +246,9 @@ module Mongo
       start_time = Time.now
       loop do
         if (Time.now - start_time) > @timeout
-            raise ConnectionTimeoutError, "could not obtain connection within " +
-              "#{@timeout} seconds. The max pool size is currently #{@size}; " +
-              "consider increasing the pool size or timeout."
+          raise ConnectionTimeoutError, "could not obtain connection within " +
+            "#{@timeout} seconds. The max pool size is currently #{@size}; " +
+            "consider increasing the pool size or timeout."
         end
 
         @connection_mutex.synchronize do
@@ -300,5 +290,18 @@ module Mongo
         end
       end
     end
+
+    private
+
+    def close_sockets(sockets)
+      sockets.each do |socket|
+        begin
+          socket.close unless socket.closed?
+        rescue IOError => ex
+          warn "IOError when attempting to close socket connected to #{@host}:#{@port}: #{ex.inspect}"
+        end
+      end
+    end
+
   end
 end
diff --git a/lib/mongo/util/pool_manager.rb b/lib/mongo/util/pool_manager.rb
index 0525ec4..019ead2 100644
--- a/lib/mongo/util/pool_manager.rb
+++ b/lib/mongo/util/pool_manager.rb
@@ -84,6 +84,10 @@ module Mongo
       @refresh_required
     end
 
+    def closed?
+      pools.all? { |pool| pool.closed? }
+    end
+
     def close(opts={})
       begin
         if @primary_pool
@@ -114,6 +118,10 @@ module Mongo
 
     private
 
+    def pools
+      [@primary_pool, *@secondary_pools]
+    end
+
     def validate_existing_member(member)
       config = member.set_config
       if !config