diff --git a/pymongo/mongo_client.py b/pymongo/mongo_client.py
index 7920b6a53..5d4703c0e 100644
--- a/pymongo/mongo_client.py
+++ b/pymongo/mongo_client.py
@@ -1421,12 +1421,15 @@ class MongoClient(common.BaseObject):
                 # be a persistent outage. Attempting to retry in this case will
                 # most likely be a waste of time.
                 raise
-            except Exception as exc:
+            except PyMongoError as exc:
                 if not retryable:
                     raise
-                # Add the RetryableWriteError label.
-                if (not _retryable_writes_error(exc, max_wire_version)
-                        or is_retrying()):
+                # Add the RetryableWriteError label, if applicable.
+                _add_retryable_write_error(exc, max_wire_version)
+                retryable_error = exc.has_error_label("RetryableWriteError")
+                if retryable_error:
+                    session._unpin_mongos()
+                if is_retrying() or not retryable_error:
                     raise
                 if bulk:
                     bulk.retrying = True
@@ -2170,7 +2173,7 @@ def _retryable_error_doc(exc):
     return None
 
 
-def _retryable_writes_error(exc, max_wire_version):
+def _add_retryable_write_error(exc, max_wire_version):
     doc = _retryable_error_doc(exc)
     if doc:
         code = doc.get('code', 0)
@@ -2183,18 +2186,18 @@ def _retryable_writes_error(exc, max_wire_version):
                 "to your connection string.")
             raise OperationFailure(errmsg, code, exc.details)
         if max_wire_version >= 9:
-            # MongoDB 4.4+ utilizes RetryableWriteError.
-            return 'RetryableWriteError' in doc.get('errorLabels', [])
+            # In MongoDB 4.4+, the server reports the error labels.
+            for label in doc.get('errorLabels', []):
+                exc._add_error_label(label)
         else:
             if code in helpers._RETRYABLE_ERROR_CODES:
                 exc._add_error_label("RetryableWriteError")
-                return True
-            return False
 
-    if isinstance(exc, ConnectionFailure):
+    # Connection errors are always retryable except NotMasterError which is
+    # handled above.
+    if (isinstance(exc, ConnectionFailure) and
+            not isinstance(exc, NotMasterError)):
         exc._add_error_label("RetryableWriteError")
-        return True
-    return False
 
 
 class _MongoClientErrorHandler(object):
@@ -2232,7 +2235,8 @@ class _MongoClientErrorHandler(object):
                 self.session._server_session.mark_dirty()
 
             if issubclass(exc_type, PyMongoError):
-                if exc_val.has_error_label("TransientTransactionError"):
+                if (exc_val.has_error_label("TransientTransactionError") or
+                        exc_val.has_error_label("RetryableWriteError")):
                     self.session._unpin_mongos()
 
         err_ctx = _ErrorContext(
diff --git a/test/test_examples.py b/test/test_examples.py
index 16e1936d5..c0913b34c 100644
--- a/test/test_examples.py
+++ b/test/test_examples.py
@@ -842,7 +842,6 @@ class TestSampleShellCommands(IntegrationTest):
 
 
 class TestTransactionExamples(IntegrationTest):
-    @client_context.require_version_max(4, 4, 99)  # PYTHON-2154 skip on 4.5+
     @client_context.require_transactions
     def test_transactions(self):
         # Transaction examples
diff --git a/test/test_transactions.py b/test/test_transactions.py
index ff707c5f9..85345e274 100644
--- a/test/test_transactions.py
+++ b/test/test_transactions.py
@@ -415,13 +415,7 @@ def create_test(scenario_def, test, name):
     @client_context.require_test_commands
     @client_context.require_transactions
     def run_scenario(self):
-        try:
-            self.run_scenario(scenario_def, test)
-        except OperationFailure as exc:
-            if (client_context.version.at_least(4, 5) and
-                    client_context.is_mongos and exc.code == 13388):
-                self.skipTest('PYTHON-2189 Ignoring StaleConfig error: %r' % (
-                    exc.details))
+        self.run_scenario(scenario_def, test)
 
     return run_scenario