diff --git a/Lib/tarfile.py b/Lib/tarfile.py
index 9dd8601cb63..26f9c7f6acf 100644
--- a/Lib/tarfile.py
+++ b/Lib/tarfile.py
@@ -357,7 +357,7 @@ def close(self):
             self.buf = ""
             if self.type == "gz":
                 self.fileobj.write(struct.pack("<l", self.crc))
-                self.fileobj.write(struct.pack("<L", self.pos))
+                self.fileobj.write(struct.pack("<L", self.pos & 0xffffFFFFL))
 
         if not self._extfileobj:
             self.fileobj.close()