diff --git a/Docs/Changelog_sm5.txt b/Docs/Changelog_sm5.txt
index 74705dbfe4..72fc9f1bbb 100644
--- a/Docs/Changelog_sm5.txt
+++ b/Docs/Changelog_sm5.txt
@@ -8,6 +8,11 @@ ________________________________________________________________________________
 StepMania 5.0 Preview 4 | 2011100?
 --------------------------------------------------------------------------------
 
+2011/10/04
+----------
+* [NoteDataUtil] More accurate Left, Right, and Mirror mods for Pump gameplay.
+  Major thanks to Hudson Felker and Bill Shillito here. [Wolfman2000]
+
 2011/10/01
 ----------
 * [ScreenHighScores] Disable forced screen transition behavior when
diff --git a/src/NoteDataUtil.cpp b/src/NoteDataUtil.cpp
index b195ebf0e5..d5cbc1d8b8 100644
--- a/src/NoteDataUtil.cpp
+++ b/src/NoteDataUtil.cpp
@@ -1161,16 +1161,16 @@ static void GetTrackMapping( StepsType st, NoteDataUtil::TrackMapping tt, int Nu
 			break;
 		case StepsType_pump_single:
 		case StepsType_pump_couple:
-			iTakeFromTrack[0] = 3;
-			iTakeFromTrack[1] = 4;
+			iTakeFromTrack[0] = 1;
+			iTakeFromTrack[1] = 3;
 			iTakeFromTrack[2] = 2;
-			iTakeFromTrack[3] = 0;
-			iTakeFromTrack[4] = 1;
-			iTakeFromTrack[5] = 8;
-			iTakeFromTrack[6] = 9;
+			iTakeFromTrack[3] = 4;
+			iTakeFromTrack[4] = 0;
+			iTakeFromTrack[5] = 6;
+			iTakeFromTrack[6] = 8;
 			iTakeFromTrack[7] = 7;
-			iTakeFromTrack[8] = 5;
-			iTakeFromTrack[9] = 6;
+			iTakeFromTrack[8] = 9;
+			iTakeFromTrack[9] = 5;
 			break;
 		case StepsType_pump_halfdouble:
 			iTakeFromTrack[0] = 2;
@@ -1209,9 +1209,58 @@ static void GetTrackMapping( StepsType st, NoteDataUtil::TrackMapping tt, int Nu
 
 		break;
 	case NoteDataUtil::mirror:
-		for( int t=0; t<NumTracks; t++ )
-			iTakeFromTrack[t] = NumTracks-t-1;
-		break;
+		{
+			switch (st)
+			{
+				case StepsType_pump_single:
+				case StepsType_pump_couple:
+				{
+					iTakeFromTrack[0] = 3;
+					iTakeFromTrack[1] = 4;
+					iTakeFromTrack[2] = 2;
+					iTakeFromTrack[3] = 0;
+					iTakeFromTrack[4] = 1;
+					iTakeFromTrack[5] = 8;
+					iTakeFromTrack[6] = 9;
+					iTakeFromTrack[7] = 2;
+					iTakeFromTrack[8] = 5;
+					iTakeFromTrack[9] = 6;
+					break;
+				}
+				case StepsType_pump_double:
+				case StepsType_pump_routine:
+				{
+					iTakeFromTrack[0] = 8;
+					iTakeFromTrack[1] = 9;
+					iTakeFromTrack[2] = 7;
+					iTakeFromTrack[3] = 5;
+					iTakeFromTrack[4] = 6;
+					iTakeFromTrack[5] = 3;
+					iTakeFromTrack[6] = 4;
+					iTakeFromTrack[7] = 2;
+					iTakeFromTrack[8] = 0;
+					iTakeFromTrack[9] = 1;
+					break;
+				}
+				case StepsType_pump_halfdouble:
+				{
+					iTakeFromTrack[0] = 5;
+					iTakeFromTrack[1] = 3;
+					iTakeFromTrack[2] = 4;
+					iTakeFromTrack[3] = 1;
+					iTakeFromTrack[4] = 2;
+					iTakeFromTrack[5] = 0;
+					break;
+				}
+				default:
+				{
+					for( int t=0; t<NumTracks; t++ )
+						iTakeFromTrack[t] = NumTracks-t-1;
+					break;
+				}
+			}
+			break;
+		}
 	case NoteDataUtil::shuffle:
 	case NoteDataUtil::super_shuffle:		// use shuffle code to mix up HoldNotes without creating impossible patterns
 		{