diff --git a/rhodecode/api/utils.py b/rhodecode/api/utils.py
--- a/rhodecode/api/utils.py
+++ b/rhodecode/api/utils.py
@@ -351,7 +351,10 @@ def get_pull_request_or_error(pullreques
     return pull_request
 
 
-def build_commit_data(commit, detail_level):
+def build_commit_data(rhodecode_vcs_repo, commit, detail_level):
+    commit2 = commit
+    commit1 = commit.first_parent
+
     parsed_diff = []
     if detail_level == 'extended':
         for f_path in commit.added_paths:
@@ -362,8 +365,11 @@ def build_commit_data(commit, detail_lev
             parsed_diff.append(_get_commit_dict(filename=f_path, op='D'))
 
     elif detail_level == 'full':
-        from rhodecode.lib.diffs import DiffProcessor
-        diff_processor = DiffProcessor(commit.diff())
+        from rhodecode.lib import diffs
+
+        _diff = rhodecode_vcs_repo.get_diff(commit1, commit2,)
+        diff_processor = diffs.DiffProcessor(_diff, format='newdiff', show_full_diff=True)
+
         for dp in diff_processor.prepare():
             del dp['stats']['ops']
             _stats = dp['stats']
diff --git a/rhodecode/api/views/repo_api.py b/rhodecode/api/views/repo_api.py
--- a/rhodecode/api/views/repo_api.py
+++ b/rhodecode/api/views/repo_api.py
@@ -317,17 +317,18 @@ def get_repo_changeset(request, apiuser,
             'ret_type must be one of %s' % (
                 ','.join(_changes_details_types)))
 
+    vcs_repo = repo.scm_instance()
     pre_load = ['author', 'branch', 'date', 'message', 'parents',
                 'status', '_commit', '_file_paths']
 
     try:
-        cs = repo.get_commit(commit_id=revision, pre_load=pre_load)
+        commit = repo.get_commit(commit_id=revision, pre_load=pre_load)
     except TypeError as e:
         raise JSONRPCError(safe_str(e))
-    _cs_json = cs.__json__()
-    _cs_json['diff'] = build_commit_data(cs, changes_details)
+    _cs_json = commit.__json__()
+    _cs_json['diff'] = build_commit_data(vcs_repo, commit, changes_details)
     if changes_details == 'full':
-        _cs_json['refs'] = cs._get_refs()
+        _cs_json['refs'] = commit._get_refs()
     return _cs_json
 
 
@@ -398,7 +399,7 @@ def get_repo_changesets(request, apiuser
         if cnt >= limit != -1:
             break
         _cs_json = commit.__json__()
-        _cs_json['diff'] = build_commit_data(commit, changes_details)
+        _cs_json['diff'] = build_commit_data(vcs_repo, commit, changes_details)
         if changes_details == 'full':
             _cs_json['refs'] = {
                 'branches': [commit.branch],