diff --git a/connector/src/main/java/org/jboss/as/connector/subsystems/datasources/DataSourceModelNodeUtil.java b/connector/src/main/java/org/jboss/as/connector/subsystems/datasources/DataSourceModelNodeUtil.java
index 1862fb5..3ca38c2 100644
--- a/connector/src/main/java/org/jboss/as/connector/subsystems/datasources/DataSourceModelNodeUtil.java
+++ b/connector/src/main/java/org/jboss/as/connector/subsystems/datasources/DataSourceModelNodeUtil.java
@@ -171,8 +171,7 @@ class DataSourceModelNodeUtil {
         final boolean setTxQueryTimeout = getBooleanIfSetOrGetDefault(operationContext, dataSourceNode, SETTXQUERYTIMEOUT, Defaults.SET_TX_QUERY_TIMEOUT);
         final TimeOut timeOut = new TimeOutImpl(blockingTimeoutMillis, idleTimeoutMinutes, allocationRetry,
                 allocationRetryWaitMillis, xaResourceTimeout, setTxQueryTimeout, queryTimeout, useTryLock);
-        final TransactionIsolation transactionIsolation = dataSourceNode.hasDefined(TRANSACTION_ISOLATION.getName()) ? TransactionIsolation
-                .forName(dataSourceNode.get(TRANSACTION_ISOLATION.getName()).asString()) : null;
+        final TransactionIsolation transactionIsolation = getTransactionIsolationIfSetOrGetDefault(operationContext, dataSourceNode, TRANSACTION_ISOLATION, null);
         final String checkValidConnectionSql = getResolvedStringIfSetOrGetDefault(operationContext, dataSourceNode, CHECKVALIDCONNECTIONSQL, null);
 
         final Extension exceptionSorter = extractExtension(operationContext, dataSourceNode, EXCEPTIONSORTERCLASSNAME, EXCEPTIONSORTER_PROPERTIES);
@@ -252,8 +251,7 @@ class DataSourceModelNodeUtil {
         final Boolean setTxQueryTimeout = getBooleanIfSetOrGetDefault(operationContext, dataSourceNode, SETTXQUERYTIMEOUT, Defaults.SET_TX_QUERY_TIMEOUT);
         final TimeOut timeOut = new TimeOutImpl(blockingTimeoutMillis, idleTimeoutMinutes, allocationRetry,
                 allocationRetryWaitMillis, xaResourceTimeout, setTxQueryTimeout, queryTimeout, useTryLock);
-        final TransactionIsolation transactionIsolation = dataSourceNode.hasDefined(TRANSACTION_ISOLATION.getName()) ? TransactionIsolation
-                .forName(dataSourceNode.get(TRANSACTION_ISOLATION.getName()).asString()) : null;
+        final TransactionIsolation transactionIsolation = getTransactionIsolationIfSetOrGetDefault(operationContext, dataSourceNode, TRANSACTION_ISOLATION, null);
         final String checkValidConnectionSql = getResolvedStringIfSetOrGetDefault(operationContext, dataSourceNode, CHECKVALIDCONNECTIONSQL, null);
 
         final Extension exceptionSorter = extractExtension(operationContext, dataSourceNode, EXCEPTIONSORTERCLASSNAME, EXCEPTIONSORTER_PROPERTIES);
@@ -365,4 +363,17 @@ class DataSourceModelNodeUtil {
             return null;
         }
     }
+
+    private static TransactionIsolation getTransactionIsolationIfSetOrGetDefault(final OperationContext context, final ModelNode dataSourceNode, final SimpleAttributeDefinition key, final TransactionIsolation defaultValue)
+            throws OperationFailedException {
+        String value = getResolvedStringIfSetOrGetDefault(context, dataSourceNode, key, null);
+        if (value != null) {
+            TransactionIsolation transactionIsolation = TransactionIsolation.forName(value);
+            if (transactionIsolation == null) {
+                transactionIsolation = TransactionIsolation.customLevel(value);
+            }
+            return transactionIsolation;
+        }
+        return defaultValue;
+    }
 }