diff --git a/deepdiff/helper.py b/deepdiff/helper.py
index 5143a3b7..8cb6cfa2 100644
--- a/deepdiff/helper.py
+++ b/deepdiff/helper.py
@@ -691,9 +691,10 @@ def datetime_normalize(
         datetime.timezone, "BaseTzInfo"
     ] = datetime.timezone.utc,
 ) -> Any:
-    # A plain date has no time component, so truncation does not apply to it.
-    has_time = not (isinstance(obj, datetime.date) and not isinstance(obj, datetime.datetime))
-    if truncate_datetime and has_time:
+    # Only datetime and time objects carry truncatable time fields. A plain
+    # date has no time component, and other types (e.g. timedelta) do not
+    # support .replace() with time fields, so truncation skips them.
+    if truncate_datetime and isinstance(obj, (datetime.datetime, datetime.time)):
         if truncate_datetime == 'second':
             obj = obj.replace(microsecond=0)
         elif truncate_datetime == 'minute':
diff --git a/tests/test_diff_datetime.py b/tests/test_diff_datetime.py
index c3905291..880e458e 100644
--- a/tests/test_diff_datetime.py
+++ b/tests/test_diff_datetime.py
@@ -1,5 +1,6 @@
+import pytest
 import pytz
-from datetime import date, datetime, time, timezone
+from datetime import date, datetime, time, timedelta, timezone
 from deepdiff import DeepDiff
 
 
@@ -123,3 +124,23 @@ def test_datetime_within_array_with_timezone_diff(self):
         assert not DeepDiff(d1, d2)
         assert not DeepDiff(d1, d2, ignore_order=True)
         assert not DeepDiff(d1, d2, truncate_datetime='second')
+
+    def test_truncate_datetime_with_timedelta(self):
+        """truncate_datetime must not crash on timedelta (no .replace())."""
+        for truncate_datetime in ('second', 'minute', 'hour', 'day'):
+            d1 = {"a": timedelta(days=1)}
+            d2 = {"a": timedelta(days=1)}
+            assert not DeepDiff(d1, d2, truncate_datetime=truncate_datetime)
+            d2 = {"a": timedelta(days=2)}
+            assert DeepDiff(d1, d2, truncate_datetime=truncate_datetime)
+
+    def test_truncate_datetime_with_np_datetime64(self):
+        """truncate_datetime must not crash on np.datetime64 (no .replace())."""
+        np = pytest.importorskip("numpy")
+        from deepdiff import DeepHash
+        for truncate_datetime in ('second', 'minute', 'hour', 'day'):
+            h1 = DeepHash(np.datetime64('2020-05-17'), truncate_datetime=truncate_datetime)
+            h2 = DeepHash(np.datetime64('2020-05-17'), truncate_datetime=truncate_datetime)
+            assert h1 == h2
+            h3 = DeepHash(np.datetime64('2020-05-18'), truncate_datetime=truncate_datetime)
+            assert h1 != h3